Partition magic is a nice program, but its expensive(Or wait for a deal at frys with rebate then you can get it for alot cheaper), when alterativly you can use the software that came with your harddrive(or download from their site) or depending on how you want to do it, if you have the 300GB all in one right now and you have everything installed and dont want to reformat then you couldn't do it this way, but if your OK with refomating then you can boot of of the windows Disk and have it make two partitions in there.