no video with win2k or xp, works fine with win98

Hi, I recently bought an used old compaq 5bw250 it came with no hd. I installed win 98 and it works fine so I decided to install winxp on it, the installation went fine it boot up to the desktop and in about 4 to 5 minutes it lost video, also the cd drive and video drive will not open.
I rebooted, it went to the desktop again with no problem and then lost video again. I tried win2k, same as with win xp it loses video after booting to the desktop and no power to the cd and dvd drives.
Can someone help me please, do you think I need a more powerful power supply or bios updateor or am I stuck with win98. I already tried different video card and different monitor so I know it's not that.
Thanks in advance

 

Agree with your guess about the psu, and that's not expensive to replace, assuming a standard model. Certainly doesn't sound like the video card. or windows, although you would be wise to be sure your video and motherboard drivers are correct for XP.