Can I change partition sizes

I have a computer C Drive 30 GB which is out of space and an H drive with about 80 GB most of which is available (about 15 GB used)

Can I use a program like partition magic to moe space from the H drive to the C drive or because it is all formatted already do I have to reinstall the OS and repartition.

Theoretical question. Why do people take a good C drive and intentionally make it smaller with different program and data drives. It seems to be a situation which just invites this type of problem.

Thanks for any help

Yes. If you're using Vista, it has a built in repartioning system. If you're using XP you'll have to buy Partition Magic, or use gparted from a knoppix boot disk.

gpartd is free, open source, works well. You may want to try it before paying for Partition Magic. That said, I've paid for several versions of PM over the years, its a good product.

The reason that I would partition a single disk into C: and D: drives, and put all the programs and data on D: is so that I could easily do a "format c:" periodically and clear out all the crap that Windows seems to collect.

With good tools, resizing is no big deal

I think that it is possible, but if you are looking to keep performance on your pC in the same way I'm afraid that reinstalling OS will be needed.

i would highly suggest partition magic or paragon partition manager.

they can both work under vista or xp.

use with care and read what to do, do try to do any shortcuts.

AND MAKE SURE TO CHKDSK YOUR DRIVES BEFORE HAND.

ANY errors on your drive will interrupt your integrating, thus resulting in a fail partition, making the file system unreadable.

Actually, in addition to chkdisk mentioned upthread.

Be sure to backup all of your important data before you start. Most of the time, changing the partition is easy. Sometimes it goes wrong and you can lose the data. Do your backups.