very strange red line on the top of my screen

[abracadabra1]

hmm...something strange is definately going on.
it seems like every time my cpu temp hits 120 i get a red line across the top of my computer and it's frozen.
is this some sort of hardware protection by win2k (only happens in win2k, not me)? could it possibly be a hardware monitor of the sort?
comp specs:

abit kt7-raid
amd duron600@1026 @1.8V
256MB PC100 cl2 Kingston valueram w/ infineon chips at 141MHz cas2
ibm 75gxp 45GB HD
adaptec 2930c scsi controller card
matushita 4X scsi cdr
leadtek geforce2mx (205/188)
soundblaster pci512
3com 3c905btx 10/100 nic
linksys network anywhere 10/100 nic
win2k/winme dual boot

 

[AlphaIVT]

i use to get green vertical lines about 1/4" long from the top of the screen sometimes, and my computer froze during that time. i was on win98