so do you have 300 gb? or only 71 mb? because if its 71 mb, u have got some major cleaning to do. I doubt that though, some viruses clutter the hard drive. If you have plenty of room, and your still getting the message then you can follow these instructions to remove the annoying message. Low Disk Space Warning in Vista - Vista Forums
1. open regedit
2. go to HKEY_CURRENT_USER\SOFTWARE\Microsoft\Windows\CurrentVersion\Policies\Explorer
3. Right click explorer and then select new then DWORD (32 bit value)
4. name it NoLowDiskSpaceChecks
5. right click it and press modify
6. change its value to 1 in hexadecimal form then press ok
7. log out and back in and message should be gone.