Keep in mind when your computer was new out of the box and super-fast? Those were the days, when boot times were less than the time it takes to hard-boil an egg.

All computers slow down with use. The more you uninstall and install software, delete and add files, change personal preferences and tweak system configurations, the more you leave a trail of file remnants, registry conflicts, fragmented drives, and errors that impair PC performance.

Even a new computer may show premature signs of “age” — that is, longer processing times, system crashes, and programs that lock up inexplicably. The frustrated computer owner may give up on an “old” PC with perfectly good hardware to buy a brand new unit — just to repeat the cycle.

Insufficient memory, spyware, and worn-out hardware are normally blamed for waning performance.

At the same time, while spyware’s a factor in numerous computer slowdowns, it’s rarely the only factor. And while your system may have loads of RAM, it still won’t suffice if your system manages memory badly.

As for the age of your hardware, there’s no physical reason why it should run any slower than the day you bought it.

So what’s the truly behind all those computer slowdowns?

The top 4 PC speed killers are:

1. Registry Errors, Clutter, and Fragmentation

Your Windows registry contains key information for everything on your system, including software settings, user profiles, hardware configurations, etc.

As you engage in your ordinary computing activities, the registry gradually fills with clutter and begins to create errors. Why? Because long after you’ve uninstalled a download, references to that download remain in the registry, leaving Windows to deal with invalid paths.

During start up, Windows tries to load all the missing drivers, applications, and files still listed in the registry, making the boot process something like the hunt for specific phone numbers in a poorly organized address book.

Compounding the issue, your registry gets fragmented just like your hard drive. Since the registry has to be loaded into memory every time you start your system, the bigger and more fragmented it is, the longer you’ll wait for your computer to go through its paces.

2. Hogging the Starter’s Position

Numerous programs load themselves partially whenever you start your computer. This makes them appear more responsive when you launch them, but with so many programs starting at once and tapping system resources, boot times and overall performance suffer.

You may want to preload a couple of favorite programs for quick access, but not all those seldom-used utilities queuing up on your taskbar.

3. Bad Internet Settings

90% of PCs owners haven’t optimized their internet settings. In case you’re among this group, you’re losing bandwidth, and perhaps even permitting malware to pirate portions of your bandwidth to run on your computer. Unless you optimize the way your PC communicates with the network, downloads will probably take longer than they should, and web pages may be slow to load — even over a fast connection.

4. Hard Drive Errors

Over 26% of all computers have hard drive errors. These degrade performance and may prevent you from saving or retrieving files. Worse, hard drive errors may be an indication of imminent mechanical failure that could cost you all your data.