major pc problem...please help:(

i dont know if this is a SW or HW problem, so ill post here anyway. my pc is having random freezes. sometimes it just hangs for 30 secs, icons dissapear on DT, then reapear again. but sometimes it totally freezes and i have to reeboot. then sometimes it wont reboot at all until like after 5 tries.
if this is any help, i get a ieexplore.exe application error (put decimals here)blah blah" sometimes when im shutting the pc down. anyway, i did all my virus scans (avg newly updated) performed spyware tests (spybot, adaware, yahoo spy) defraged....
specs are
ati radeon 9600pro
winxp
1gb ram
2 hard drives totalling 140gb
amd athlon3200+xp

thanks in advance guys

 

sounds like it could be excessive heat. is the inside of your computer relatively dust-free?

and as for the desktop icons problem (and i'm assuming the start menu is gone too), it is explorer crashing then loading up again (since explorer is rigged to restart after a sudden crash). if the icons don't appear again, press ctrl + shift + esc, then click on file / new task, and type in "explorer.exe" without quotes.