I'm having a major malfunction

So I dont know what the heck happened, but on my desktop computer I have been locked out of everything..

My only account it (Home)
it WAS administrator

but now its guest, I cant make any changes or do anything that requires administrator privileges unless I get a
UAC box where it says Yes/No at the bottom but yes is grayed out unless I

"enter the administrators password"

which to my knowledge I have never set one....

I have tried the back door of changing rights to this account = failed
opened cmd prompt to enable the hidden administrator = failed

so without completely reformatting because i never set a backup im hooped.... any ideas

thanks;

403Phaze

Run a full scan with Malwarebytes Download in Safe Mode with Networking if necessary.

If this fails try booting to run a full scan with one of the FREE Bootable AntiVirus Rescue CDs Download List.

If it cleans up infection then try SFC SCANNOW Command or SFC SCANNOW Run in Command Prompt at Boot.

Now try regular boot. If it fails again try Built-in Administrator - Enable from WinRE - Windows 7 Forums.

Unfortunately if you cannot access Hidden Admin and have no functionality from your Admin Account, then unless you can run a Repair Install it may be beyond Repair. Best to invest further time in doing a perfect Clean Reinstall Windows 7 which compiles everything that works best in tens of thousands of installs we've helped with here, and has been used by 1.5 million consumers without a single complaint.