Explorer.exe not funtioning.. Need help

[infested]

Ok, here's the problem. Whenever I run Windows XP Professional, my desktop shows and all the icons on it, and so does the start-menu bar.. Well, at least the start-menu icon and the time shows, not MSN messenger and all those other icons. When the arrow is on the desktop, it shows "not working", I can't click any icon (won't highlight), and whenever I move the arrow onto the start-menu bar, it shows "working". Although, my comp is silent as hell, and nothing actually happens. I had the computer on for 3 hrs, nothing happened.

I have now switched to Windows 98 which also is installed on my computer, and I'm wondering.. What is there to do? Will I have to re-install Windows?

[Link]

PC specs ?