I think you mean SIS 650. It is needed to make display for PCs with the SIS M650, SIS 650GX, SIS 650 or SIS 740 graphics controller. It is supported by Windows XP and 2000.
The NVIDA drivers on your PC were properly outdated and was not supported by the new SIS 650 update. That might be the source of your conflict.
I have no idea on what to do on getting your graphics back.
I got a used computer for my son and for some reason it wasn't able to play CD/ROM games as it did before a friend downloaded a file. Checking the system's device manager it seemed to be a conflict between two display adapters, one was from NVIDIA and the other one started with SYS 650 something. This last one was downloaded by my friend last week in order to solve some sound problems.
In order to make the story short I uninstalled the SYS 650 thinking that the problem of the games would be solved.
Unfortunately now my computer turns on but the monitor is showing no signal.
What can I do?