Installing Windows 7 update or new hard drive?

Having an issue with a virus or effects from a virus removed. I recently got a new anti-virus (Kaspersky 2010) cause it was obvious I had a virus. So I wanted to check my hard drive for errors and do a defrag after doing a full scan and deletion or qurantine. Neither will let me. After researching how to do a recovery, I tried to run a recovery from the Windows safe mode menu (F8). Well everytime I try, it gets a blue screen of death and restarts. Also when the computer boots normally, it sometimes goes to a black screen with the mouse. If I upgrade to Windows 7 will it try to fix some of those errors, or should I just get a new hard drive and install a full Windows 7?