Help?! Windows 7 keeps logging me on as default user!

The desktop is empty, most programs won't start with error message about internet security settings

I have tried restarting my PC 3 or 4 times, but it keeps happening (normal and in safe mode)

I can SEE my normal user profile in:

C:\Users\Adam (but it has a padlock over it)

Every time I reboot I get prompted to put my password in as "Adam" but then it goes to the Default Profile. In the Event Logs the error message is just this (over and over):

(18 of these) Windows cannot load the user's profile but has logged you on with the default profile for the system.

DETAIL - Access is denied.

(1 of these) Windows cannot load the locally stored profile. Possible causes of this error include insufficient security rights or a corrupt local profile.

DETAIL - The process cannot access the file because it is being used by another process.

(2 of these) Windows was unable to load the registry. This problem is often caused by insufficient memory or insufficient security rights.

DETAIL - Access is denied. for C:\Users\TEMP\ntuser.dat

_

Any one have any ideas?

The only thing I did last time I was logged on (which maybe wasn't a good idea) was download and install a version of Civilisation II I found on the web (but I did some checks on the site I got it from, and everywhere I check said it was legit...)