Hello...
The size of the Registry is not limited by RAM, virtual memory, or hard disk (unless the HDD is completely full of course).
On Windows 2000, the maximum size of the system portion of the Registry was 12 MB.
On Windows XP, the maximum size of the system portion of the Registry increased to 200 MB.
You would see the message you're getting whenever a program tried to add a key or value to the system portion of the Registry.
It's very curious that your SYSTEM file is 12 MB, the old limit, and are getting messages indicating the system portion of the Registry is full. For comparison, my Windows XP SP1 SYSTEM file is only about 3.5 MB.
If you are so-inclined: The system portion of the Registry is that which is below "HKEY_LOCAL_MACHINE\System" key. You can browse this by running "regedit.exe".
WHAT DO YOU DO?
1. Do you have any idea why your SYSTEM file is so large (12 MB whereas mine is just 3.5 MB)?
2. Be sure your system is not infected with any malware (virus, etc).
3. I don't know how to adjust the maximum Registry size on Windows XP. The place where it was set is no longer there. It used to be in:
My Computer->R-Click->Properties->Advanced Tab->Performance Section->Settings button->Advanced Tab->Maximum Registry Size section
-----Steve Jackson
CEO/CSA
Software Corporation (Softcorp)
http://www.softcorp.us/probono
Advanced pro bono tools and utilities free for personal use