Problem booting, need major help

[kill4killin]

Ok, well i just got a PIII computer from a friend of mine when he upgraded to a new computer recently. It worked fine and dandy and then i made some upgrades. Mainly the graphics card...it again worked fine for a little while. After that it started to boot but would not show anything on the monitor. I figured it was the graphics card not getting enough juice from the low wattage PSU. So i put a smaller 4mb graphics card in since it was going to just be a terminal server for file storage on my network. However, it still would not boot. So i took it out of the case and tried running it bare with now case so that working on it would be easier. It worked, but when it started to boot it would start to check the devices and then come up with a message saying "press a key reboot" and then go through the same process and say the same thing. This is where I am stuck now. I figured you guys might be able to help me since this is a VIA PIII system. Does anyone have any idea what is going on with this thing?