Well, everything worked fine in my Ubuntu 10.10, until I restarted the PC and I got this message from a hard disk I've been using before with ubuntu:
Error mounting: mount exited with exit code 16: Mount is denied because the NTFS volume is already exclusively opened.
The volume may be already mounted, or another software may use it which
could be identified for example by the help of the 'fuser' command.
Any ideas?Please help!

Thank you!