From Birnam Designs Wiki

when you restart Vista (perhaps after a crash) and a default/temp profile is used

open regedit, find profile in reg: HKEY_LOCAL_MACHINE\Software\Microsoft\Windows NT\CurrentVersion\ProfileList

your profile will probably be with a .bak extension, with the normal profile linking to a C:\Users\Temp user location

Reset refcount to 0, status to 0x80 (128 decimal)

rename normal profile (Temp) with a .temp extension

duplicate the .bak one to the normal name (I did this by exporting the .bak to a .reg file, renaming the key in the .reg file with a text editor by taking out the .bak in the name, and then re-importing it)

log off / log back in