NT generates an alert window when the free space remaining on a partition falls below 10%. With 13GB HDs available and very large partitions in common use, this is not useful since there could easily be 1.3GB free. Cut and paste the following code into hdfull.reg file and run it.

REGEDIT4
BLANK LINE GOES HERE
[System\CurrentControlSet\Services\LanmanServer\Parameters] "DiskSpaceThreshold"=dword:1
BLANK LINE GOES HERE

The change will take effect immediately. After applying this registry change to my PC, the alert should pop up at 1%, for my 13GB partition (down to 130MB free space). NT2000 compatible .reg file. Set DiskSpaceThreshold to a percentage that fits your situation.

See .REG files for background information on .REG files.