Slow computer?

I don't know why my computer is running slow. I've done antivirus scans, defrags, disk cleanups, and deleted programs I don't use but still no improvement. I can barely use any programs, can't view videos very well because it lags so bad, I can't listen to music because it keeps cutting and skipping no matter what program I use, internet is slow as well, there are NO viruses, even booting up takes a while. I haven't had these problems before. I need help.

I'm using Windows XP

I checked the properties on My Computer and it says I have 640 MB of RAM

I have two hard drives:

my (C:) drive has 139 GB free space and

my (D:) drive has 246 GB free space

P.S. Please understand that I WILL NOT do those registry cleanups or go-download-this-program-to-make-my-comp... crap so don't bother promoting because I won't do it.

Slow computer?antivirus protection

You can try to do the following.

Click start , then run

Type msconfig

A window opens with many tabs: general, system.ini..

Click the last tab which is startup. You will see that many programs are clicked. Unclick all of them (diable all), most of them are unnecessary and run in the background taking up space, if the system needs them during startup it will take care of it, so dont have to worry if you unclicked a necessary program.