A couple of months ago i downloaded a custom logon screen, and used this Logon Loader program to install it. Then in the following weeks, whenever I tried to boot the computer it would stop responding either right before windows loaded, right after windows loaded, right after i logged on, or sometimes 30 minutes after i logged on. I'm not sure if the logon screen was the cause for this but today my computer did this automatic disk cleanup thingy, and it deleted the logon screen or maybe something necessary to load it. Instead of showing the welcome screen, a window pops up that says "This application has failed to start because LSASRV.dll was not found. Reinstalling the application may fix this problem." After the OK button is clicked then i'm left with a black screen and a cursor and I can't log in. How can I fix this?