Bootcamp Error Message Updating WinXP to SP3.

With more than enough drive capacity available on my Bootcamp partition, upon attempting to update my version of Win XP to Service Pack 3, kept getting the error message:

"There is not enough disk space on C:\WINDOWS\$NtServicePackUninstall$ to install Service Pack 3 Setup requires an additional 4 megabytes of free space or if you also want to archive the files for uninstallation,Setup requires 4 additional megabytes of free space. Free additional space on your hard disk and then try again".

Not sure if I'd call this a 'fix', but the workaround for this issue was a Registry hack, by adding a registry key and tweaking, as follows:


1. Click Start – Run – Type “regedit” and press enter.
2. Navigate to

[HKEY_LOCAL_MACHINE\Software\Microsoft\Windows\CurrentVersion\Setup]

HKEY_LOCAL_MACHINE
    \Software
         \Microsoft
              \Windows
                  \CurrentVersion
                       \Setup
                     
3. In the right pane, Right-click and select New – String value
4. Name it as “BootDir” and set it's value to “C:\”
Without even rebooting, SP3 immediately installed itself with no further anomalies. (Note: As with both platform's 'Software Update' routines, (thank God), the download itself (a little over a Gig) usually residing in a "temp" directory, which then goes 'poof!', was seen by XP, and only the 'Install' was performed). I wish Adobe's temp folders would also hang onto their downloaded files which never got installed, before their script(s) run, deleting any remnants of the downloaded files.