Malware attack please help me out.

Hello, First off all thank you for reading this.
Now about my problem...some malware disabled my RPC service which causes a lot of problems. I scanned my PC with updated AVG and he found something and delete it.
My PC is clean of viruses now (at least AVG says so) but problems which virus have caused aren't gone yet.
RPC service is on automatic but still turned off and when I try to start it manualy it shows me an error 5: access denied which means that I don't have admin rights and I don't know how to return my admin Rights.
I'll tell you few more symptoms to make your job easier.... I can't access internet explorer but other browsers like mozilla and chrome are online.
Than I can't see services properties and can't see external services only standard (most of them are turned off)
When I want see external services It shows me an error:
One or more ActiveX controls could not be displayed because your current security settings prohibit running activeX controls on this page or you have blocked a publisher of one of the controls.
Also when I go to security policy I can't see properties either.
All in all I need somebody who can tell me how to get my administrative Rights back so that I can enable RPCs (remember I'm logged on as Admin)
Please don't suggest me reinstaling of windows because I bought it few years ago and don't know where cd and activation key is, than system restore because it's unavailable (RPC must be online to do that) and also I've tried some methods like this code run:
secedit /configure /cfg %windir%\repair\secsetup.inf /db secsetup.sdb /verbose
but it doesn't work too.
My os is xp pro sp3
PLEASE HELP FAST IM DESPERATE !
Cheers!