When starting your TTU domain computer, Windows takes a long time to load the sign-in box or verify your credentials.

The computer must establish a network connection before it can verify your username and password.

Check the computer's network connection, including the network cable, the port, and the network settings on the computer. If everything is OK with the network connection, then perhaps some software or hardware problem on the computer is slowing the connection. If you are able to sign in, use anti-virus and anti-spyware software to run scans to check for possible infections.