lately my computer has been really messed up. at random times the "Explorer" will preform an illegal operation and shut everything down in the bottom right cornor except the sound and MSN messenger. Also the active desktop needs recovering all the time. Also my computer will freeze ALL the time for no reason. Sometimes programs wont work and it usually takes three times restarting to get everything to work for a little while. Ive updated Norton Anti-Virus a hundred times...ran hundreds on different scans and it never finds a virus. ANY help would be great

Dimension XPS T700r

Win 98se

512SDRAM

700Mhz P3

GeForce 256APG

SB Live