Welcome back
Sounds like you have more than 1 partition like I have.
I use 2 HD's with 6 partitions.
C, M and P drives on the original hard drive.
D: is the C/D -
M is for music and P is for program file exe's to re install.
X, Y and Z on the largest hard drive.
Keep back ups, and anything important OFF the C Drive.
If you get a virus, such as this, simply reformat the C: drive, (yeah it sucks but hey) you won't lose anything important, like back ups.
You'll have to reinstall all your program files - but the set up files should be on another drive, like drive P - so just click and install.
(oh, and keep a text file of the license or install numbers)
It still sucks the big one - but in an afternoon, you'll be back and running.