If your computer is slow and un responsive at times, it might have a virus.  Now a lot of people right away take this to a fix it shop and fork some dough to have it delt with.  There are alot of great Anti virus programs on the web now for windows vista.

Before you are ready to give up on your machine, try downloading a free anti  virus program and letting it do a system scan.  I have found that even with a computer that is full of problems, a free virus scan can get it functioning in as little as 30min.

One of the best Anti Virus programs out there is Avast! www.avast.com They have been around for a long time, and they do have a free version.  It does require you to register and get a registration number in your email.  They dont spam you and their product is great.  After using the free home version, I’m sure alot of people end up buying the paid versions for the corporate offices.