doing full factory restore to remove virus's

Hey does doing a full factory system restore on a dell remove virus/malware or does the virus/malware find a way to restore itself?

A computer tech friend of mine said to wipe out the "safe portion" of your hard drive and reinstall windows fresh.  What is your take on that guys?  Is there a way to delete the safe portion of a hard drive?

(can someone tell me how to do a full system factory restore on a dell i will try that method first) thanks guys!