Windows may have filled your H:Drive with System Restore Points.
FOR WINDOWS XP:
By Default, Windows will save your System Restore Files on both Partitions of your Hard Drive. Right Click on My Computer and click Properties. (Or go to Control Panel and double-click the System icon)
Click the System Restore Tab at the top of the Window that pops up. In that box in the middle should be a listing of the C: and H: Drive. Click the H: Drive to highlight it and Click the Settings button.
On the next Window click the box that says: Turn off System Restore for this Drive. This will stop putting System Restore points on the H:Drive and it will also remove the System Restore Points already saved to the H:Drive.
Click Start and then right click Computer and click Properties. Or in the Start menu, click Control Panel, and on the left hand side click Classic View. Then double click the System icon and on the left hand side again, click Advance System Settings.
Click the System Protection tab at the top of the box. The uncheck the box beside the H:Drive in the box under Automatic Restore Points.
If Windows tried to perform an automatic backup:
The Recovery Files should be hidden on your recovery partition H:. At the top of the screen in the H:Drive click Tools > Folder Options
Click the View Tab and go down the list of Advance Options and clcik in the circle to "Show Hidden Files and Folders"
If you computer used the WIndows Backup and Restore to backup files, look for a Folder Named PC-"Your WIndows User Name", with the name of your Windows Login after the PC-
If you don't see that folder, don't delete anything else.
If you do see that folder you can delete it You can open that folder and see the files that were stored. That is the backup Windows created and by default the Windows Back Up and Restore program likes to choose the first partition that is not the C:Windows partition. Do Not Delete anything else.
You can go to your Program Files in the Start Menu and go to the Windows Backup and Restore and in the options change the backup location to somewhere else, or turn off the automatic backup feature.
Don't use the partition set aside for the recovery for anything else or save data there.