When I try to partition my disk and install Windows on it, I get the message:
"The disk cannot be partitioned because some files cannot be moved.
Back up the disk and use Disk Utility to format it as a single Mac OS Extended (Journaled) volume. Restore your information to the disk and try using...
The command key is the equivalent of a control key on a PC.
eg. intstead of CTRL-Z to undo something you do CMD-Z.
And yes, it would be pretty bad not to have one if you own a Mac.