Troubleshoot an Asrock P4VM890 Motherboard

Question

I can't seem to find anywhere to troubleshoot the motherboard in XP home...I just got this less than a year ago, and there are some weird signs that just came up...it shut down once on it's own (don't know the error code) and things are going much slower all the sudden...also, the fan is louder than it was...PS- any advice about free antivirus/spywear?