What is your Hard Drive Type/Configuration?
First, you say you changed the video card. I don't think too much of ATI cards used with Linux, but I am not sure you have went far enough for video to be a problem. None the less, I might switch back to the ordinal video to see if that does anything different. I have found that nVidia cards work much better with Linux and work fine with Windows as well.
Many times, when SuSE will not reboot the first time, it is because the hard drive configuration is wrong for some reason. For instance, I like to load SuSE on an external USB hard drive. Doing so most often will not survive the reboot because when you actually boot from the USB hard drive, your logical drive designations for HD0 and HD1 change as the drive you boot from is always HD0. Thus problems can exist in the /boot/grub/menu.lst, /boot/grub/device.map and sometimes /etc/fstab files.
Why not give us a little more information about you hard drive: Is it PATA or SATA and do you have a USB hard drive in the mix. Do you know the hard drive partition setup? You will need a SWAP file and a root partition for Linux, but other partitions can exist or be left alone. What is the hard drive size?
Next what is your memory setup? How much, speed and number of modules. Bad memory can kill an installation and is hard to determine sometimes. If you have more than one memory module, You can try them one at a tome to see if something different occurs.
Last, anything else attached to this computer. Sound cards or built-in sound, printers, USB devices and so forth. Sometimes taking the system down to the minimum to run can help get past install problems. You then add other devices back in one at a time until it is all back in.
Off hand I can't say what the problem is, but perhaps more information might help figure it out.