The User Profile Service failed the logon. User profile cannot be loaded

We have a resolution for this issue for quite a while now, but most of us are still not following the rights steps to resolve the issue. Even system restore is not a permanent solution, as we have seen customers calling back for issue being returned after sometime. Please ensure you follow the below steps to resolve the issue.

Log on with another administrator user profile or if you don’t have any other and you are the only user do the following:

1.    Turn off computer.

2.    Turn on computer and press F8 while you see the DELL logo.

3.    On the Windows Advanced Options select Safe Mode.

4.    Open the Start Menu and type Regedit on the Start Search field.

NOTE: If unable to boot to OS even in safe mode then boot to WinRE, go to command prompt - type regedit.exe to perform below steps:

5.    Go to the following entry:

a.    HKEY_LOCAL_MACHINE\Software\Microsoft\Windows NT\CurrentVersion\Profile List

6.    There you will find the following information:

7.    On the “.BAK” file you will find an entry with ProfileImagePath with the name of the user.

8.    Delete the repeated entry that does not contain “.BAK”

9.    Right click on the other entry and select Rename. Delete the extension .BAK for the original entry.

10.  Exit Regedit

11.  Restart computer.

Also Refer: http://support.microsoft.com/kb/947215/en-us