I have recently moved and my wireless reception to my PS3 is terrible so I was told I could use this other desktop, which is receiving the signal much better, as a relay point instead of buying a wireless signal repeater. How do I get this computer to also spread the signal from the original router downstairs?

I'm sorry, but there's nothing built into Windows XP that can do what you want. You might be able to do a web search and find a third-party program for that.Boulder Computer MavenMicrosoft Most Valuable Professional