Slow Boot Up

Hey all!

I am having some difficulty with my machine, in that it has started taking an extremely long time to boot up. By long time, I mean upwards of ten minutes from Power Button (or restart button) to Login screen.

First, some computer information. I have a Dell Dimension E510 running on Windows XP. It has a 3.20 GHz Pentium 4 Processor and has 1.00 GB of RAM.

When I first hit the power button (or when I restart from Windows), the first few screens appear (Dell, then Windows XP), but then the screen goes blank for almost 10 minutes. During this, the fan seems to be running at high speed. Right before the thing finally boots up (heading into the blue login screen), the fan goes quiet. Then the login screen appears. The rest of the startup process continues without much incident, but the fan starts running again at high speed (I can hear it) and doesn't turn off for almost 20 minutes after login.

I have recently defragmented my hard drive, in case that helps. I have also finished working with chaslang with some Malware issues, so my computer should be clean. I'd appreciate any thoughts. Thanks again!