Login screen - password autofocus question

I have been using Win7 for a couple of months now. With the exception of Explorer, I have been generally very happy with the OS.

Just today, something strange happened with my screen saver login screen. I searched for a while, but was not able to find anything - quite possibly because I was not using the right search terms.

Up until now, whenever I come back to my PC after a while, the login screen would show and I can type in my password immediately and log in. I am the only user on this PC. The only other account is administrator.

Starting today, for some reason, I now have to use the mouse to click on the password entry box BEFORE I type for the password to register. If I do not click on the box, the cursor in the box blinks like it has focus, but my typing is not registered.

In the overall scheme of things, this is not a big deal. But I am curious why this happened and how it might be reverted back to the way it was before.

Back in the days of XP, this happened to me AFTER I installed .NET. Apparently .NET installation creates a phantom user account. In which case, I have to select my account to login. The fix for the XP situation was to delete the .NET account. As mentioned before, I am the only user on this Windows 7 PC. Looking in Users and Accounts, I do not see any phantom users.

I have just run a scan with AVG Free which reported no problems.

Thanks again for your help.

Thanks. The system restore did the trick. Still can't figure out why this happened.