You said the installation can't be finished. This possibly means Windows 7 has encountered a driver issue. This could be anything from motherboard components to add in cards or other connected devices. I'd forget about the blaming the video card just yet. Maybe if you'd post more about your hardware someone will know of a known compatibility issue.
Ok so I have installed Windows 7 on my desktop, and I'm using a Radeon hd card which can handle almost any res i have thrown at it so far. it's a 4875 if anyone wants to know.
Anyway I have rebooted and the 7 logo comes up instead of vista( which is a relief) but when the os loads my monitor can't support the res. Is there any way to change the res b/c I can't actually interface with the os.
It hasn't asked me to input any user account names yet and I tried booting safe mode and it says that Windows cannot finish installation and restarts.
Please help.

Chowhound
Comic Vine
GameFAQs
GameSpot
Giant Bomb
TechRepublic