Thank you for your question.
I would suggest you use a free partition called "GParted" and is available under the GNU license arrangement, no price or charge. It has a very good reputation around the forums on the Internet.
http://gparted.sourceforge.net/From your question I am assuming this task falls upon you often. Might I suggest that if you have not heard/tried them to use a "Live Boot CD", I have provided a few links, they are the most popular ones. This CD's boot up independently of the Hard Drive and have many, many features included and are updated regularly. Again, these are free, no charge and fantastic support tools.
http://www.ultimatebootcd.com/
http://www.hiren.info/pages/bootcdYou will need to do a little reading to get up to speed with it, but it is worth the time and effort. As you appear computer savvy it should be an enlightening adventure.
Good luck and kind regards
