Most viruses can be manually cleaned up. Start by identifying the virus and then looking up the cleanup instructions at Symantec's website.

No one is going to be able to give you instructions on reinstalling without knowing what model system you have and how old it is.

I have several a few viruses actually and I think it would be best if I just reformatted.  I have a Dell Inspiron 5150 laptop with xp professional.  It is 1 and 1/2 years old.  I have help in reformatting I am just trying to make sure that I do it the right way.