PC Running Slow? 5 Things to Check Before Buying New

A slow computer is one of the most frustrating things to deal with — especially when you’re trying to get something done. Before you start looking at new machines, it’s worth spending twenty minutes working through a few checks. The cause of a sluggish PC is almost always one of a handful of common problems, most of which you can either fix yourself or have sorted cheaply by a local repair shop.

Here are five things to check before you give up on your current machine.

1. Check Your Startup Programs

This is the first thing to look at, and it’s the most common culprit for a PC that feels slow from the moment you turn it on. Every time Windows starts up, it loads a list of programmes automatically. Over time, this list grows — every app you install tends to add itself to the startup queue, whether you want it there or not.

To check yours: press Ctrl + Shift + Esc to open Task Manager, then click the Startup tab (in Windows 11, it might be under the Startup apps section in the Settings app instead). You’ll see a list of everything that loads when Windows starts, along with a “Startup impact” rating — High, Medium, or Low.

Anything rated High that you don’t recognise or don’t need immediately on startup is worth disabling. Right-click and choose Disable. You’re not uninstalling anything — you’re just telling Windows not to load it automatically. Common culprits include Spotify, Skype, Teams, Discord, OneDrive, various manufacturer utilities, and browser extensions.

Reboot after making changes and notice the difference. For many people, this alone makes their machine feel significantly faster.

2. Check Your Storage Space

Windows needs free space on your main drive to function properly. It uses that space for temporary files, virtual memory, system updates, and general housekeeping. When you fall below roughly 10-15% free space, performance degrades noticeably. Below 5%, things can get very slow indeed.

Open File Explorer and right-click on your C: drive, then choose Properties. The pie chart will show you how full the drive is. If you’re running low:

• Search for “Disk Cleanup” in the Start menu — Windows’ built-in tool can often free up several gigabytes by removing temporary files, old Windows update files, and cached data.
• Check your Downloads folder. It’s remarkable how many gigabytes accumulate there without anyone noticing.
• Look at large files you no longer need. Windows’ “Storage Sense” feature (Settings > System > Storage) can help identify what’s taking up space.

If your drive is genuinely full because you have a lot of data, the longer-term solution is either clearing out old files or upgrading to a larger drive. An SSD swap — replacing your old hard drive with a fast solid-state drive — is one of the most cost-effective upgrades you can make to an older PC, and it’s something PC Express handles regularly.

3. Run a Malware Scan

Malware, adware, and spyware are surprisingly common causes of a slow PC — and they often go unnoticed because the symptoms look identical to a hardware problem. A programme running quietly in the background, consuming CPU cycles and network bandwidth, will slow your machine down without leaving any obvious clues.

Windows Defender (now called Microsoft Defender Antivirus) is built into Windows and is genuinely capable. Open it by searching for “Windows Security” in the Start menu, then choose “Virus & threat protection” and run a full scan. A full scan takes longer than a quick scan but checks everything.

If the scan finds something and has trouble removing it, or if you suspect something is running that Windows Defender hasn’t flagged, this is a good point to bring in a professional. Spyware removal is a common job at PC Express, and we use specialist tools that go deeper than consumer antivirus software.

Signs that malware might be your problem include: browser homepage has changed without you doing it, lots of unexpected pop-up ads, the PC is hot and the fan is loud even when you’re not doing much, or you’ve noticed strange network activity.

4. Check Your RAM Usage

RAM (Random Access Memory) is where your computer stores the data it’s actively working with. If you run out of it, Windows starts using a portion of your hard drive as “virtual memory” — which is dramatically slower. A machine with 4GB of RAM running a modern browser with several tabs open, Teams, and a few other applications is going to struggle.

Open Task Manager (Ctrl + Shift + Esc) and click on the Performance tab, then select Memory. You’ll see a graph of RAM usage over time and a current percentage. If you’re consistently sitting at 85% or above during normal use, you’re running out of RAM and your PC is compensating by slowing down.

The fix for this is a RAM upgrade — adding more memory sticks (or replacing existing ones with higher-capacity modules). How much RAM your PC can accept depends on the motherboard, and whether it’s upgradeable at all depends on the machine. Desktops are almost always upgradeable. Laptops usually are, with some exceptions.

A RAM upgrade is one of the most affordable performance boosts available. In Sale and the Manchester area, expect to pay roughly £40–80 for an upgrade including parts and fitting, depending on how much RAM you need and what type your machine takes.

5. Check for Windows Updates and Driver Issues

This one gets overlooked, but it matters. Outdated drivers — particularly graphics drivers — can cause performance issues that look like hardware problems. An out-of-date chipset driver, for example, can throttle performance significantly. Similarly, Windows update issues (a stuck update, a failed update, or an update that installed incorrectly) can cause persistent background processes that consume CPU time.

Check for Windows updates by going to Settings > Windows Update and running a check. If there are updates pending, install them and reboot. If an update is stuck or failing, that itself needs resolving.

For drivers, the Device Manager (search for it in the Start menu) will show any devices with errors flagged with a yellow warning icon. You can also visit your PC manufacturer’s website and check the support downloads section for your model — many manufacturers release driver update tools that handle this automatically.

If you find that Windows Update keeps failing, or that drivers seem to reinstall correctly but problems persist, this is often a sign of a deeper Windows corruption issue that may require a clean install to properly resolve.

When To Call a Professional

You’ve worked through the five checks above and the PC is still slow. Or you’ve found the problem but you’re not comfortable fixing it yourself. This is exactly what a local repair shop is for.

At PC Express in Sale, the most common PC performance jobs we handle are:

Clean Windows Install

Sometimes a PC has accumulated so much cruft — failed updates, corrupted system files, software conflicts, registry issues — that the only reliable fix is a fresh start. A clean install of Windows wipes everything and starts from scratch. We back up your personal files first, reinstall Windows, reinstall your applications, and restore your data. The result is a machine that performs as it did when it was new. This typically costs in the region of £60–80 for a standard PC or laptop.

SSD Upgrade

If your machine still has a traditional spinning hard drive (HDD), replacing it with a solid-state drive (SSD) is the single biggest performance upgrade you can make. SSDs are typically 5–10 times faster at reading and writing data than HDDs, which means Windows loads faster, applications open faster, and the whole machine feels more responsive. The drive cost varies by capacity, but including fitting and data migration, an SSD upgrade in Sale typically runs to £80–140 for most machines.

RAM Upgrade

As mentioned above, if RAM is your bottleneck, adding more is an affordable fix. We’ll check what your machine supports, source the right type, and install it. Most desktops and many laptops can be upgraded to 8GB or 16GB, which is enough for comfortable everyday use in 2026.

Malware Removal and System Clean

If software is the problem — adware, spyware, browser hijackers, or general software bloat — we’ll clean it up properly. This includes running specialist removal tools, checking browser extensions, cleaning up scheduled tasks, and making sure nothing is reinstalling itself in the background.

Is It Worth Repairing or Should I Buy New?

This depends on the age and specs of the machine. A PC that’s 4–6 years old and has an SSD and at least 8GB RAM is almost certainly worth investing in a clean install or software fix. A machine that’s 8–10 years old with a very low-end processor may genuinely be reaching the end of its useful life.

If you’re not sure, bring it in and we’ll give you an honest assessment. We’re not going to recommend a repair that costs more than the machine is worth — if you genuinely need a new machine, we’ll tell you that. But in our experience, most “the computer’s just slow” complaints are fixable without buying anything new.

PC Express offers computer repairs and laptop repairs in Sale, Greater Manchester. Pop in, give us a call, or get in touch online — we’ll take a look and give you a straight answer about what’s going on and what it’ll take to fix it.