help! cant open anything - Moved

[dontknow]

Hi guys,
the other day my friend inserted his external hard drive in my computer. I think it was infected. After that I havent been able to open anything. I keep getting the message: "This operation has been cancelled due to restrictions in effect on this computer. Please contact your system administrator."
I cant open the registry either. Cant open antivirus as well. Cant access the D drive as well. But i can access programs from another account. So i tried running gpedit.msc to allow regedit to run but on the other account everything seems fine and there is no trace of regedit or any other program being blocked. My friend says it must be this virus called "mayday". He says the only solution is to reformat the C drive. I thought i'd ask you guys for some solutions.
Thanks,
dontknow

[Budfred]

We are going to need info... Please post a HijackThis log to begin:

http://www.merijn.org/programs.php

To run HJT, extract it to a permanent folder such as one you create like C:\HJT or the Desktop. Close all open windows and
browsers and make sure that all programs are enabled if you use msconfig. Run it and Scan, then Save the log.
When the log window appears, Right click to Copy it, open your browser and come here to Paste the entire log. Do
not make any changes until it is checked since most items are either benign or essential to the computer. Make sure that WordWrap is turned off in Notepad
and use as many posts as needed to paste it all here...

And we might as well look at a ComboFix log as well...

1. Download this file - combofix.exe (http://download.bleepingcomputer.com/sUBs/ComboFix.exe)
2. Double click combofix.exe & follow the prompts.
3. When finished, it will produce a log for you. Post that log in your next reply

Note:
Do not mouseclick combofix's window whilst it's running. That may cause it to stall...

I am moving this to the appropriate forum for a security issue...