Oh well, one less Gvardia!

I jk Pedrophile.

Try creating a new account on your computer and then run GTA SA off that account, worked for me in the past when it simply wouldn't launch without even an error.
Other things I can think of:
Run as administrator.
Try running in different compatibility modes.
Restore your computer to a time when it worked? (If it worked in the past 3 weeks since you bought your PC).