Yes; you can replace your bios chip cheaply by going to ebay and typing a search for "bios chip"
I dont think that is your problem though. Try a PCI slot video card and pull your current AGP card. If you dont have a PCI slot card >>>> you can generally pick one up dirt cheap ($5.00) at any PC repair shop. It does not have to be any wiz bang card; just plain old vanilla; for testings sake
Those PSU's you have will be very under powered for that system >>> you should be running at least 500 watts >>>> a good reasonable priced one is the Antec SP-500 for $68.00 I have not seen a PSU that can be bought for less thats any good .
Does the CPU fan spin and stay running ?????? >>>>> it it does then the CPU self test is passing >>>> try the board with only stick of memory
post back your troubleshooting results
