To disable the low diskspace notification:
Start the Registry Editor
Go to HKEY_CURRENT_USER \ Software \ Microsoft \ Windows \ CurrentVersion \ Policies \ Explorer \
Right-click an empty space in the right pane and select New > DWORD Value
Name the new value NoLowDiskSpaceChecks
Double-click this new value, and enter 1 as it's Value data
Close the registry editor
Log off, or restart Windows for the changes to take effect
Note: This will turn of the Low Diskspace warning on all your drives!