How can I simulate a disk full error in a Windows environment?
You could try writing to a full floppy disk.
Edit:
In light of your edited question, you could set up a network share with no disk space quota and write to that. The error will then be produced regardless of the logged on user or machine.
For Windows XP or later:
This command can get the amount of free space for the c:\ drive:
for /f "usebackq tokens=1-5" %%A in (`dir c:\ ^| find "bytes free"`) do ( set FREE_SPACE=%%C)Replace c:\ with your drive, as needed.
You can then take some space away from this value so you have a little room to work with:
set /a FREE_SPACE=FREE_SPACE-1024or however much space you want to keep free.
You can use the fsutil command to create a file to fill up the free space on the disk:
fsutil file createnew c:\spacehog.dat %FREE_SPACE%Run your test, writing to the drive. After you write 1024 bytes or so you should run out of space.
Download and install TrueCrypt. You can then create a virtual partition of whatever size you want (a couple of megabytes), mount it and then fill it with a couple of documents.