Here's the pertinent article for Windows XP.
An error message informs you that you cannot move or rename the Documents
and Settings folder
http://support.microsoft.com/kb/314843/
To me that looks like an awful lot of work when there are easier
alternatives to address this problem. First off, here are some steps you
can take to free up space on the C drive.
1. Relocate the My Documents folder to the D drive. Take a look at this
article
for more info.
How to Change the Default Location of the My Documents Folder
http://support.microsoft.com/?id=310147
2. Reduce the amount of hard drive space allocated to System Restore.
Go to Control Panel and double click the System icon.
Click on the System Restore tab.
Under Available drives, click on the C drive so it's highlighted.
Hit the Settings button.
Move the slider to the left so it reserves no more than a GB of HD space.
3. Reduce the amount of space allocated for Internet Explorer's
cache.
Go to Control Panel and double click Internet Options.
Hit the Settings button in the Browsing history section on the General
page.
Note: Hit the Settings button in the Temporary Internet Files section of
the
General page if using IE6.
Reduce the amount of disk space used to something between 50 and 100 MB.
4. Reduce the amount of space used by the Recycle bin.
Right click the Recycle bin icon on the Desktop and select Properties from
the
menu.
Move the slider to the left. 5% should be more than enough.
5. Remove Windows Update uninstall files.
The files used to uninstall updates to Windows can be deleted
if you're confident that they will not have to be uninstalled
in the future. These files can be found in the Windows folder
with names similar to this $NtUninstallKB123456$. They are
hidden folders so make sure you enable viewing of hidden files
and folders in Control Panel -> Folder Options -> View tab.
Note: Do not delete the $hf_mig$ folder. This folder will be
used by future updates.
Here's a web site which provides an automated way of deleting
these folders.
Courtesy of Doug Knox, MS-MVP
Removes Hotfix Backup files and the Add/Remove Programs
Registry entries.
http://www.dougknox.com/xp/utils/xp_hotfix_backup.htm
6. Relocate the storage location for files used to store email. How this
is done depends on the program used.
Finally, resizing the partitions is an option. You can download a thirty
day trial version of this program to perform this task.
BootIT Next Generation
http://www.terabyteunlimited.com/bootit-next-generation.htm
Keep in mind that any important files should be backed up before making
any changes to the hard drive.
Good luck
Nepatsfan