constantly rebooting

[John TUrner]

I have a system
450 amd k6III
128 MB ram
20Gb hdd
cdrw
ati 128 rage vidio card
modem 56k pci

once i install windows xp home addition the system trys to
boot, then once the logo screen is up the system will
restart itself.

I blew away the image formatted the drive into 2 10GB
drives, reinstalled xp in fts format.
the problem remains the same, I have swapped system boards
with a known good brd. CPU with a 1000GB amd(known good)
removed the modem card. swapped the ram (known good.
the problem persists. at one point I had reinstalled the
os 7-8 times and the os seemed ok, for about 2 weeks. now
the problem is back. it will not b oot to the os, only the
logo (not log on) the little stream of lights go from left
to right 1-2 times while I look at the black back ground,
and windows xp logo then back to the boot screen testing
memory and displaying drives ect.
any ideas?
John

 

[Mike]

Have you scanned for viruses?

 

[Tom]

Try reseating everything. Cables, boards, etc. Blow out dirt and dust.
Got a spare power supply? Try changing cables.
Tom