The Same Old Problem, the Same Old Trap
Your PC is running slow. You go to YouTube, find a guide with 200,000 views, the guy in the video runs PowerShell commands copied from the description and swears that "your PC will be like new again." Twenty minutes later your PC is still slow — and you've got a toolbar you can't remove as a bonus.
Self-education is right, I even encourage it. That's how I got where I am. The problem isn't learning on your own — it's doing it without method, from unverified sources. That said, let's talk about what actually works.
First: Check Your Disk
Before downloading anything, open File Explorer and see how much free space you have on drive C. If you're above 80% usage, you've found your first culprit.
Windows uses the disk for virtual memory and system operations — with little free space, it slows down everything, silently and progressively. Below 15% free space, problems start. Below 10%, the system becomes almost unusable.
What to do: empty the trash, move or delete large files you don't use, uninstall unused programs from Settings → Apps. Only then move to the next step.
Defragmenting Your Disk: A Practice to Retire
If you've bought your PC in the last six or seven years, it almost certainly has an SSD. On an SSD, defragmentation is not only useless — it's harmful. SSDs have a limited number of write cycles: defragmenting uses them up without providing any benefit. Windows 10/11 already knows this: when you select "Optimize Drive" on an SSD, the system runs TRIM, which is a completely different and correct operation.
On a mechanical HDD disk, defragmentation still makes sense, but Windows manages it automatically in the background on a weekly basis. You don't need to do it manually.
In practice: anyone who tells you "defragment your disk to speed up your PC" is giving you advice from the Windows XP era. Forget about it.
CCleaner: Still Valid in 2026
I haven't changed my mind about CCleaner. It's free, does what it promises, and in years of professional use I've never seen it cause data loss. Its reliability is why I still use it as my first intervention.
Pay attention to where you download it from. In 2018 CCleaner was hit by a supply chain attack — for a period the distributed version contained malware. Download it only from the official site ccleaner.com, never from mirrors, never from links in YouTube descriptions.
Step 1 — Open CCleaner, go to Custom Cleaning. You'll find the standard categories already selected: temporary files, browser cache, system logs. For a first use that's fine.
Step 2 — Click Analyze. CCleaner scans and shows you how much space it will free up. If you have browsers open it will ask you to close them — do it, otherwise it won't touch the cache.
Step 3 — Click Run Cleanup. Done.
The System Registry: Here's the Thing
CCleaner also has a registry cleanup function. I need to be honest: Microsoft itself officially advises against registry cleaners. The benefit is marginal — a few kilobytes — and the risk, though contained with a serious tool, is not zero.
My advice: if you don't know exactly what you're doing, skip this section. Cleaning temporary files gives you 90% of the benefits without any risk.
Programs That Start with Windows
This is often the real culprit behind slowness, more than any temporary files. Every installed software tends to add a startup service — automatic updaters, sync clients, players, software you used once in your life. They accumulate, consume RAM, and slow down startup without you noticing.
CTRL+SHIFT+ESC → Startup tab in Task Manager. Sort by Startup Impact — you'll immediately see the culprits. Right-click → Disable on everything you don't use daily. Don't touch antivirus, audio/video drivers, or system services you don't recognize.
Windows Updates: Professional Management
Microsoft releases updates regularly — and not all of them come out stable. Over the years I've seen updates cause downtime on business installations: drivers that stop working, printers that become unreachable, management applications that crash.
For offices, even small ones: keep updates in manual mode. Let your IT person evaluate the stability of a patch before rolling it out. Waiting a few days after a major release isn't laziness — it's risk management. If you have critical management software, this goes double.
For home use: automatic updates remain recommended for security vulnerability coverage. But a recent backup before a major update never hurts.
How Often
For home use: whenever you feel something isn't right. No fixed schedule.
For an office, even a small one: every 45 days is a reasonable cadence if you don't have RMM software monitoring machines in real time. With RMM your IT staff intervenes before the user notices a problem — without it, scheduled maintenance is the only way to stay ahead.
What's Not in This Guide
Antivirus deserves its own article — and it will get one. Choosing between consumer and business solutions, when antivirus isn't enough, endpoint protection: topics too important to dismiss in a line.
For today: check your disk, forget about defragmentation, clean temporary files, check startup, manage updates methodically. Five concrete things — methodically, as I said.