Don't install any additional software to fix this. Any "registry cleaners", anti-spyware can only add more problems, viruses,... (at least suggested by someone you don't know).

You can get the blue screen of death because of a virus, hardware problems, or software problems.

You can get a virus by visiting a web-site, reading an e-mail (especially when you open attachments and visit shady web-sites, but not only them). You can even get a virus when you don't update your OS, don't use a firewall.

Switch from Windows to Linux and you will have way much safer Internet