[sonneti]

What OS, what GFX card's are you running?

Have you tried bypassing the programs that startup automatically? (hold down shift when the windows screen pops up during boot)

Have you tried playing without firewall/anti-virus protection?

What about the remote desktop software you are using logmein.exe?

You could also try a fresh install of XP, just install the minimum to a new folder leaving your current install untouched.