Question : Problem: Reinstalling iPod after Re-formatting Computer Hard Drive

I'm having some serious problems with my hard drive on my computer, which may require me to either re-format the C: drive or buy a new computer.  I am concerned that I might be unable to reinstall my iPod (and my girlfriend's iPod) to our computer after we format the drive and/or after we buy a new one.

Isn't there a limit on the number of computers on which you can install an iPod?  We've had to do this several times before and I am afraid that I might have run out of computers.

Answer : Problem: Reinstalling iPod after Re-formatting Computer Hard Drive

The answer you're looking is in here
http://www.experts-exchange.com/Apple/Hardware/iPODs/Q_22462109.html
You can copy your music form the Ipod to the PC,
So you can reformat youor computer, I recomend having two partitions, one for the OS and the programs, the other for your personal stuff like music.
The follow the instructions on the refered question to recover your music, one folder per IPod, then on ITunes add the folder to the play list of the IPod.