Verified answer

The removal of administrator rights is a possible indication of malware on your machine. If you have an anti-virus, I think you should update it and run it. (If you don't, many people around here recommend AVG. I use Norton, so I can't vouch for it.)

I suggest you download Ad-Aware SE and Spybot S&D (they’re free), install them, update them and run them. If any of them don't seem to be able to get rid of everything they report finding, try running them again, this time in Safe Mode. Safe Mode often prevents the malware from running and protecting itself.

Also, turn off System Restore to evict any copies of bad stuff that might be lurking there.

To get into Safe Mode:

1. Log out and reboot your machine.

2. When the machine starts the reboot sequence, press the F8 key repeatedly.

3. Select Safe Mode from the resulting menu.

4. The machine will continue booting, but the Windows desktop will look different. You won't be able to see the Internet, for instance. Log in as Administrator. Administrator often has no password.

5. When you're finished, log out and reboot back into normal mode.

Update and run both regularly, along with a good anti-virus package.

Good luck.