If you mean reinstalling the OS, this might be one of the best options, but it might also be a good idea to remove any viruses first.
I have had certain problems with my desktop pc,but I just re-format the Hard Disk first and re-install the OS.
It might be a good idea to install anti-virus software and a program called Zone Alarm, which will prevent any hackers and prevent any spyware attacks.
If you can boot from a CD rom with your operating system on it, this should give a complete clean installation, and you would really need to re-format the hard disk before re-installing the OS.
Hope this helps
Kenno1
May 2010