Is my video card dead????

i took the video card out of my dell to try to put it into my gateway and it turns out it didnt work but when i put it back into the dell when i turned the computer on all that showed was a bunch of garbled "matrix" type image and after a few minutes it just went to black so does it sound like its broken or what.... if it helps there was tons of thick dust caked inside maybe it just needs to be cleaner out of something i dont know if it is broken can someone suggest a similar or slightly better card it was a ati radeon x800 gto