lost video after installing ram

Archived from groups: comp.sys.hp.hardware (More info?)

I installed an additional 64meg of ram on my hp 6745c. I had to
actually remove the screws holding the motherboard in place to get to
the ram slots. I got the ram in and I verified that the ram was
detected and could notice the difference in the speed of applications
opening. I shutdown the computer, put the motherboard back in place
and put the cover back on. I powered the pc up and i get no video. I
took everything back apart and still get no video. any ideas?