Vista fast user switching disappeared

My fast user switching option in Vista Home machine suddenly disappeared. I remember it was there, then it was not. I don't know why this happened, but here is how to fix it.

A rough translation:

Run regexit.exe
Go to HKEY_LOCAL_MACHINE > SOFTWARE > Microsoft > Windows > CurrentVersion > Policies > System
Look for a key named HideFastUserSwitching. If it exists, change it's value to 0 (zero). If it does not exist create it as a DWORD and set it to zero.
You might need to log off before the change takes effect.