I'm having a SIMILAR problem with a friend's board/system.
[continuous reboots]
ORIGINALLY:
Gigabyte GA7vrx
with AMD 1.2 GHz Duron; (Socket A = Socket 462)
256 MB DDR ram
AGP (ATI XPERT2000Pro)
WD hard drive
ASUS 52X CD ROM
---this is an ATX system
System is NOW:
I changed Mobo to Chaintech 7CTKJD
then Changed existing DDR 256 stick to a new one; 266 Mhz
Tried a different AGP (ATI; Rage 128)
Tried 3 different power supplies--used one I know works well
Tried 2 different CPU's (Duron, Sempron, roughly 1.2 GHz, 1.4)
Symptoms:
With ORIGINAL SYSTEM:
Power on only showed solid POWER and HDD light; no spin up of hard drive nor CDROM boot/check. Black screen, fans spin, no other life at all.
After some/all component changes
[1] Changed motherboard 1st thing, after that, all existing components put back in actuall booted and POSTed, went to CMOS to check if it detected everything ok (yes), exited....so begins the continuous reboot cycles (but at least it's more than NO SIGNS OF LIFE).
[2] made other changes (Memory, AGP, Power supplies, and finally the CPUs. Symptoms remain the same as far as continual reboots. Details on that below.
COLD BOOT:
After mem test or after cancelling or after going in to CMOS and making changes OR NOT and exiting it will go into a continous REBOOT CYCLE. It POSTS with one beep; once mem test done/cancelled it reboots again.
*****Sometimes it will alllow me to press DEL and get into CMOS config, but saving or not and rebooting causes continual reboot loop
WARM BOOT: never gets me anywhere, ALWAYS reboots after mem check done or cancelled.
PLEASE NOTE that I could only get to a mem check EVERY TIME by setting CMOS to NOT do quick POST. With Quick POST it would beep once and reboot before I even see the "energy star" / Mem check screen.
TWICE from a cold boot I have gotten as far as the 'windows did not shutdown properly, selecte if you want safe mode/normal boot, blah blah'. Hitting any choice cause instant reboot.
It seems like I have the best chance of getting to go in to CMOS if I have left the power off for awhile (15+ minutes?)....this generally requires the Power supply switch to be TURNED OFF. Turning it back on gives me an instant boot; usually does boot such that I can get into CMOS.
Also note: I have tried MANY times to clear the CMOS via jumper (done properly with power off as mobo manual suggests) then put jumper back to normal position and apply power again. Really doesn't seem to make any difference except when I DO get back in CMOS I can see it has been cleared.
ODDly, CMOS usually detects the HDD, but sometimes it does NOT. Not sure why. I hooked it up to MY good computer as a slave and it's perfectly readable (has XP on it; didn't see which SP version)
Any suggestions PLEASE? I'm at wit's end on this one.
Thanks,
-Brew