Initially the Data partition holds the recovery system, the system you can boot from to restore your computer to factory settings if something goes utterly wrong. Windows and most programs however are found on the C partition. Normally it is a bad idea to modify the recovery partition at all; it can change the MBR in such a way that you cannot boot from it and therefore cannot restore your system. The first thing that you should do is find some DVD's and burn recovery disks (I believe that Toshiba provides a program called Toshiba Recovery Disk Creator) which you will be able to use to restore your system in the unfortunate event of some problem occurring.
Once that is done it will be time to sort out the space problem. One common cause of recovery drives filling up is that Windows Backup has been copying all your files onto that drive. Press Start and type "Backup status and configuration" Make sure that it isn't backing up to E:.
Then you'll simply have to go onto the drive and delete the files that are taking up space and that you don't need. I would suggest downloading the program
JDiskReport to help with this process. If you scan E with it, it will give you a nice pie chart breakdown to identify the significant folders. You can decide what you actually need and what you can dump.
Finally use a compression program such as Winzip or Winrar. If you don't have one installed I'd suggest the completely free
7zip. If there are files on E that you need to keep, but do not regularly need to use compress them into an archive which will take up less space. It does work better for some file types than for others; documents will compress well whereas Jpeg pictures and videos tend to be just as large as when they were loose on the drive.
Edited by Ehsanit, 10 November 2010 - 02:57 PM.