Does anyone know how to transfer programs/files from one hard drive to the other on the same computer?

if i am correct is your D drive actually a different drive OR is it a partition as i wud suspect (may say FAT under the D drive icon in my computer). if it is a partition the D drive is usually for recovery. i wud suggest that you cleanup your C drive with software, delete old files etc, defragment your drive, etc. otherwise buy a new hard drive (i managed to get a 160GB one for £40 GBP) or use an external hard drive. providing you have an extra space in your computer you can add a new hard drive - however windows xp will continue to run on your C drive unless you change it.

click and drag basicly unless the D drive is locked more info needed

If you have the install .exe or disks, just install on spare drive, then uninstall on the main hd. When you download, or have something running like a torrent client, it always ask where do you want to keep it, just point to the spare drive the next time, and change the prefered place to store in your programs.

uninstall some softwares installed on c drive and reinstall it to D drive.... byebye