OK, you may have already done these things to get more disk space. I take it you are using Windows.
Empty the recycle bin.
Use Disk Cleanup to remove temp files and other deletable items.
Take any pictures, documents and music files and move them onto a CD/DVD or (dare I say) floppy.
Defrag likes ram as well dick space so shut down background running programs (taskbar).
While you are doing maintenance, run scan disk also.
Hope this helps
Well most obvious solution is to get a new harddisk,its pretty cheap nowadays. But I guess, you might have ruled it out in the first place. So, I think these are your options:
1) If you are using Windows XP, disable System Restore. I know thats a very good feature, but I guess if you have so much low space you can disble it. If you cannot do that, then atleast delete all but most recent restore point. This should free up from 1-2GB of space depending on your settings.
2) Again in Windows XP, if you are using FAT/FAT32 then convert it to NTFS. After converting enable "Compress disk to save space". This step may reduce your disk access speed a little bit but that will be unnoticable in normal operation.
3) Download CCleaner from internet. It is a freeware and will clear out all temporary files etc. from your computer.
4) Zip off your less needed files, this will save lots of space.
first try these steps, there are some other "extreme" ways also, which are a bit risky . I can provide them if needed. But first try these steps.
If you have any problem in any of the steps, I would be more than happy to guide you.
Moved to Computer Problems and Support.
check your recycle bin. it also occupies space in drives. it must be empty. disable system restore on that drive