Ever since then it NEVER loads properly: every time I boot it up, the taskbar completely freezes and no windows can be opened (which means no task manager).
I press the shutdown button one short press (on some computers, such as mine, this triggers the shutdown procedure). A window pops up saying it's ending a program. I try to move my mouse to the "End Now" button, but the fact that at that point my computer runs at 3 frames per second makes it a pain to get there. Once I get there and click, I hear a series of random beeps and THAT'S when my computer remembers that it was in the middle of loading. At that point it starts responding, so all's well, but not, because it's already started the shutdown procedure which can't be stopped. I have to boot it up again. Sometimes it loads, but sometimes not, in which case I have to shut it down once again and boot it up a third time in Safe Mode. In Safe Mode it loads properly every time, but then I have to reboot it AGAIN, this time normally... and then it works.
Does anyone know a way to get around this? One thing I can do it boot it initially in Safe Mode, then reboot it normally, but that still doesn't get rid of the problem.
I really don't want every bootup to take 30 minutes of my day.

Specs:
OS: Microsoft Windows XP Professional, Service Pack 3
RAM: 2 GB
Processor power: Dual core 3.6 GHz
Date I got it: May 30, 2008
Plus I have 84 GB of files on my computer (where 1 GB = 1,073,741,824 bytes), in case that matters.