A slow computer is the number one reason people call me. And more often than you'd think, it turns out not to be a hardware problem at all. Before you decide your machine is past it, run through these checks. Some of them take less than five minutes.

If your computer is running slow, the most common causes are too many startup programs, low disk space, insufficient RAM, malware, or an ageing hard drive. Working through these checks methodically often restores performance without replacing the machine.

This is one of the most common issues I'm called out to fix in homes and small businesses across Uckfield and the wider East Sussex area.

Check What's Starting Up With Windows

Every time your computer starts, it loads a list of programs automatically in the background. Over time, this list grows. Spotify, Teams, Zoom, OneDrive, printer software, manufacturer utilities. They all add themselves to startup without asking, and they all slow down your boot time and eat memory while running.

To see what's starting up: press Ctrl + Shift + Esc to open Task Manager, then click the Startup apps tab. Right-click anything you don't need immediately on startup and choose Disable. You're not uninstalling it, just stopping it from loading automatically.

Common safe ones to disable: Spotify, Teams (if you don't use it daily), Zoom, Skype, printer assistant apps, manufacturer utilities like Lenovo Vantage or HP Support Assistant.

Check Your Disk Space

Windows needs free space on your main drive for temporary files, updates, and virtual memory. When a drive gets above about 85–90% full, performance drops noticeably. When it gets above 95%, things can get very slow indeed.

Open File Explorer and check how much free space you have on your C: drive. If it's under 10–15GB, that's likely contributing. Start by emptying the Recycle Bin, then run Disk Cleanup (search for it in the Start menu) to remove temporary files. Windows Settings → System → Storage will show you exactly what's taking up space.

Check for Malware

Malware, particularly cryptomining software and adware, runs silently in the background and hammers your CPU and memory. If your computer has become suddenly slower, or if the fan is running constantly when you're not doing much, it's worth ruling out.

If you have a paid antivirus installed and up to date, run a full scan. If you're relying on Windows Defender alone, run a second-opinion scan using Malwarebytes (the free version is fine for a one-off check). Download it from the official site at malwarebytes.com.

Check How Much RAM You Have

RAM is the short-term memory your computer uses for everything that's currently running. If you're trying to run modern Windows with 4GB of RAM (standard on computers sold before about 2018) you'll struggle. Windows 11 typically uses 2–4GB of RAM before you open any applications.

To check: press Ctrl + Shift + Esc, click Performance, then Memory. You'll see how much you have and how much is in use. If you're regularly at 80%+ with just a browser and email app open, more RAM would make a noticeable difference. On most laptops and desktops it's a relatively inexpensive upgrade.

Check CPU Usage

Press Ctrl + Shift + Esc to open Task Manager and look at the CPU column. If it's consistently near 100% when you're not doing much, something is running in the background that shouldn't be.

Common causes include:

  • Stuck Windows updates
  • Antivirus scans running at the wrong time
  • Browser tabs with heavy scripts
  • Malware

If you see something unfamiliar consuming high CPU, it's worth investigating.

Is the Drive Getting Old?

If your computer has a traditional spinning hard drive rather than an SSD, and it's more than 4–5 years old, the drive itself may be slowing down, or worse, starting to fail. Signs of a failing drive include very slow file operations, occasional freezes, and unusual clicking or grinding sounds.

Replacing a spinning hard drive with an SSD is the single biggest performance upgrade you can make to an older computer. A machine that takes five minutes to start and loads programs slowly will often feel like new after an SSD upgrade, for a fraction of the cost of a new computer.

Before you buy a new computer, it's almost always worth getting a second opinion. In many cases an SSD upgrade, a RAM upgrade, or a clean Windows reinstall will give you several more years of use. I see a lot of perfectly good computers thrown away unnecessarily.

When It Probably Is Time to Upgrade

That said, there are situations where a replacement makes more sense: if the computer is 8–10 years old and struggles even after a clean install, if the cost of repairs approaches the cost of replacement, or if it's a laptop with a swollen battery or physical damage.

I can help you assess whether it's worth fixing or time to move on. I'm based in Uckfield and cover East Sussex. Call me on 01825 768548 or get in touch and I'll give you an honest answer.

Most slow computer issues can be diagnosed and resolved via remote support. For hardware upgrades like SSDs and RAM, on-site support is available across the area. And for those who'd like to avoid these problems in future, GNL Protect includes proactive monitoring that flags disk health, memory and performance issues before they cause disruption.

Frequently Asked Questions

Why is my computer suddenly slow?

Sudden slowdowns are often caused by Windows updates, malware, low disk space, or a failing hard drive.

Will adding more RAM speed up my computer?

If your memory usage is consistently high, adding RAM can significantly improve responsiveness.

Is it worth upgrading an old computer?

If the machine has an SSD and enough RAM, it may have several years of usable life left. Very old systems (8–10+ years) may be better replaced.