Lost Admin password (greyed out)

I was messing around yesterday and lost my admin password option. When I try to install anything, the pop up asking for my admin pass doesn't show the regular box or take my password.
I hope this makes sense. I can't even remember what I was doing when I screwed it up. (I know people access our network but that's somebody else. They don't know anymore about network info than I do and refuse to change any settings.) That makes me paranoid. My PC doesn't have much on it. I stop services all the time when I'm not using them (like print spooler). I doing know mmc or registry stuff so it keeps me from screwing everything up.
I have a recent backup to a WD about a week ago but I doubt it will solve this problem.
Bottom line, I still have access to my standard user account and my PC seems to know that I have an admin account but I've lost the option to enter my password since it's greyed out. I've been in safe mode since.

I appreciate any help or guidance. Please don't tell me to get a new PC or buy a MAC. That really doesn't help me.

Cheers

Hello

Can you get into safe mode if so this will help.

How to troubleshoot a problem by performing a clean boot in Windows Vista or in Windows 7

Diagnostic tools to use in safe mode

How to Use Your Internet Provider in Safe Mode | eHow.com

Hope this helps please let us know.................