In windows XP it was pretty easy to remove a user profile if it had become corrupt - just delete it from the c:\Documents and Settings folder. It wasn't the correct way to do it - but it worked none the less. That's changed with Windows Vista - if you just remove the folder you will get a temporary registry when you next logon to that profile.
To correctly remove a user profile in Windows Vista.... Firstly logon using a different profile that's got admin rights to that computer.
Hit the Windows Key & Pause/Break, or go to control panel > system to see the system properties.

Click on Advanced system settings at the top left....

Under the middle 'User Profiles' click settings

Select the profile you wish to delete, and click delete.
If it's too late and you're getting the temporary registry at logon, do the following.
Open up registry editor by pressing the windows key & r, type regedit and press enter.
Go to the following registry key;
HKLM\Software\Microsoft\Windows NT\CurrentVersion\ProfileList

You'll see a list of the Security Identifiers, ignore the top 3 short numbers, they're they 'virtual' network service, local service and system profile accounts. You'll need to highlight the long SID's until you see the 'ProfileImagePath' value on the right pane that corresponds to the incorrectly removed profile.
Select that SID, and click edit > delete.
You should then be able to login and get a fresh permanent profile.