I have exactly the same video card as you in one of my machines and I have no trouble whatsoever installing VL (or any other distro for that matter) on that machine. I suggest you have one of the foolowing problems, check in the order I list below:
- you have a bad burn of the ISO; did you check the ISO with md5sum?
- you have faulty hardware
- the screensaver of your BIOS is kicking in as I said above
- you are doing something wrong during the install process