You may want to rename or move the folder in which Windows stores your profile information for one of the following reasons
•You have renamed your user account via computer management and windows still uses the folder with the old username to store your profile information.
•You want to move the profile folder from its default location to a different location for reasons like backing up, making up space in the drive windows is installed etc.
Moving or renaming your windows profile folder has 2 steps
1.Locating and renaming or moving your profile folder: You can locate your profile folder in your %SystemDrive%\Documents and Settings\Username . for example for a normail windows installation and for username ‘techallica’ the profile folder would be c:\Documents and Settings\techalllica. Now you may proceed to rename your username folder (in our case ‘techallica’) to your new username or move the username folder to another location say for ex. D:\profiles\techallica
2.Let windows know your changes: Once you have moved or renamed the folder, the next step is to register the changes in the windows registry system so that Windows knows where to locate your profile folder. To do so you need to open the registry editor by clicking on ‘run’ from the start menu and typing ‘regedit’ in the ‘run’ window. This will open up the registry editor. In the registry editor navigate to HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\ProfileList
To make things complicated windows employes something called ‘SID’ to uniquely identify user accounts. Each user account in the windows system is allotted an unique ‘SID’. You need to know the unique ‘SID’ of the user account whose profile folder you just renamed or moved. To locate the ‘SID’ just download the following script by clicking here and run it. The script will output the unique ‘SID’ of all the accounts in the system. Just note down the SID of the account being modified, get back to the registry editor, and select the correct userid. Now in the right pane, double click on ‘ProfileImagePath’ (which stores the path to the profile folder of the username) and set the correct path to the profile folder. Our case d:\profiles\techallica. If you have just renamed your profile folder then it would be C:\Documents and Settings\newusername (assuming windows is installed in C:\)
3.Done: You are done now. Just close the editor, log out of windows and login back and see if you can log back in successfully (which you most probably should)