System restore puts your pc back to the state it was before the infection, but as you said, weird things can become of it. Thats why I really don't recommend it, only as a last resort when nothing else works.
And the reason why I said you technically could still be infected is that once malware is on your system, it can hide in the system restore files so if you do a system restore you still could be infected. If a system restore is done, then you still need to scan your system for malware. System restore has a 50/50 chance of working correctly to restore your pc to a good state.
And the reason why I said you technically could still be infected is that once malware is on your system, it can hide in the system restore files so if you do a system restore you still could be infected. If a system restore is done, then you still need to scan your system for malware. System restore has a 50/50 chance of working correctly to restore your pc to a good state.