I see you run Vista 32 bit also. I can't guaranty your results because our systems are of two different classes, but with Vista I found this to work best.
Uninstall the program and do a backup or system restore point and then run Registry Mechanic. You can DL it here
http://www.pctools.com
After a good reboot and defrag install the program under “Documents/YourFolderName".
From here you can install the updates or patches as needed but you’re no longer in the realm of UAC.
This will eliminate any issues with Vista and you can look at drivers or other things from here.
Note: You can save the SH4 folder that has your configuration but you have to delete files in the “Rich Saved Games” and the folders under “SavedGames”. Just copy SH4 to another location then copy it back after the fresh install. **This will delete all saved games**
I hope this helps.