Use a virtual machine - it's free!

Are you getting viruses, spyware or other problems? Could it not be that this is happening because you are visiting dodgy websites, opening files from unknown sources, downloading "freeware" of questionable origin and suchlike? If the answer is yes, then there's no need to stop, just start being a bit more careful, that's all!

Visiting dodgy sites, downloading "freeware", or anything like that? If so, you might want to consider doing these riskfull things inside a sandbox, such as a VMware virtual machine.

You can download VMware server for free at

http://www.vmware.com/download/server/

Surf for your pr0n inside a virtual machine instead, and then your main installation - which you trust for things such as online banking and so forth - never visits a dodgy internet site.Install an XP virtual machine, patch it up by visiting windows update, and then start doing all that naughty stuff inside a VM instead!

http://www.vmware.com/download/server/

If that XP installation gets infected, just delete it and start again! Or restore from a back easily, just by copying some files.