Won't Allow Login

I've been trying to figure this out for a few hours now, and I think it would be best for me to ask some people who actually know what they're doing before I completely destroy my computer.

So here are my problems. I can't login. Whenever I try to, this message shows up: "The User Profile Service service failed the logon. User profile cannot be loaded."
So I tried to do whatever I could think of without actually logging in. First I ran a Memory Diagnostics test. Nothing was wrong, but I'm not exactly sure what that's supposed to do in the first place. Eventually, I think I got into a menu for system restore, but that wouldn't let me login using my password either. I tried the Administrator account, guest, and my own. Next, I found my way into another menu when I pressed the F2 key when the Dell symbol appeared after restarting. I went to a part of the menu labeled Security and went to the Admin Password, where I changed it. Now it says Set when it used to say Not Set. So I tried to login to the system restore again, but it still wouldn't let me login. I also tried the normal login screen.

Thanks for your help, and I hope I posted this in the right place.

Have a look at this tutorial: The User Profile Service failed the logon. User profile cannot be loaded.

Sid.

It was working great for me until I got to step eight in Fixing the User Account Profile. I don't have anything that says RefCount in the one without .bak. I tried changing the one that did have RefCount, which had .bak, and it still won't let me login.

Hi Mimih,

Welcome to Vista Forums.

I updated the tutorial by adding a NOTE under step 8 to show you how to add RefCount.

The User Profile Service failed the logon. User profile cannot be loaded.

Hope this helps,
Shawn