It seems a bit drastic just to try and get your speakers working again.
If it was me, I would start by looking at the obvious stuff like, has the volume been set to minimum or are the speakers muted in Windows. Only takes a couple of seconds to check (Start -> Control Panel -> Sounds) and could save you from having one of those
moments.
Next, check that the sound card is showing as working in your device manager, and that there isn't a yellow exclamation mark indicating a problem. You could also check that the drivers weren't affected by the virus (if that is what has caused the problem)... you could even just try uninstalling and re-installing the drivers in any case. Again, it's a lot less hassle than doing a system restore.
Just my
