"1. Defrag 'em
Before you can partition your disk, you have to make sure that all
of your data is neatly packed together. Operating systems can't
always store all bits of a file contiguously, so they're often
scattered all over the place.
"When you defrag a disk, you reduce this fragmentation and align
the blocks of data on the disk contiguously. The good news is that
defragging your disk is much simpler than its explanation.
"In Windows, head over to 'My Computer', rightclick on the drive
that you want to defrag and go to 'Properties'. Next, head over to
the Tool tab and click on the 'Defragment Now' button. Depending on
the size of the disk, the process may take several hours. Vista
defragments your drive automatically."