"Your PC" ... this indicates, that you are not talking about Windows Home Server and hence your posting is off topic here in the Windows Home Server forum.
Seems your PC has assigned you a new user profile ... sometimes this is simply solved by rebooting, sometimes there is more corrupted and you should backup your data and reinstall the OS. Rarely it is really caused by an update, more often you will see such
effects due to broken hardware, a crash damaging parts of the registry or malware.
Depending from the operating system, which you did not mention in your posting, there may be ways back, like using System Restore in Windows 7.
Best greetings from Germany
Olaf