Service (specifically RPC) admin previlidge issue in XP

Hello all,
So, I got a laptop with XP home sp3. I elevated the RPC access privilege to ./administrator (it was a network service), and before you know it, nothing is working again. I tried to go back to change it the same way I originally did (admin tools>services>RPC>properties), but it won't even let me select the expanded tab under services...just the standard one. And the properties button for ALL SERVICES, not just RPC refuses to function. (ie. click and nothing happens). Ever since the comp has had no access to RPC, everything has been malfunctioning...I guess, as expected, the start menu isn't even there, none of the network capabilities of the laptop are accessible (it doesn't even see the networks to connect to), and unfortunately, it doesn't recognize USB devices. I haven't tried if it recognizes CD's yet, but I'm doubtful it will.

Any suggestions on how to fix this?

Thanks,
John