use softwares such as Boot IT to make and undo partitions.
visit *www.bootitng.com/ and download boot it NG.
then run the downloaded DOS file and copy the contents to a floppy/CD. restart your PC, select first boot device as floppy/CD, boot from the disk. u will see that a window appears with mouse pointer saying to download the software. dont download the software 9click on no0 and u will enter in the maintenence area where u can partition/resize/delete/repartition your hard disk.
Website: *www.bootitng.com/
file size: ~600 KB