Q: Is this a possible way to sync without losing everything?

My computer has an ungodly amount of viruses on it and I've come to the conclusion that I need to reset the whole computer. My concern is losing all of my ITunes stuff in the process. I was wondering, if after it is reset, could I just 1. Restore my purchases into the new library and then 2. Redownload anything that wasn't purchased manually? It sounds good to me because all of the stuff on my IPod will be the exact same as in the library, and it could clean up any songs I wanted to delete but I never got around to doing. Please help, I'm gonna throw this computer out the window if I don't erase it soon but I wanna make sure my whole take on the process sounds foolproof.