- For programs, most installers lets you chose on which drive you want to install the program. Once installed, you can't move them, but have to uninstall from the c: and reinstall on the d:
- For your My Documents and such, use the link Bob supplied to move it from c: to d:
- For all stuff you store in a folder outside your My Documents/Pictures etc, you can make folder on any drive you want. That's fully up to you how to organise your own PC.
Things that have to be on the c:-drive:
- Windows folder
- the subfolders of Program Files and Program Files (x86) that came with Windows or the PC
- hibernate and swap file
- the Users folder with a subfolder for every user - it contains a lot of subfolders and settings that are needed, but (as Bob said) you can move your documents, video's, pictures out of it
- system restore data assocated with Windows and Program Files on the c:-drive.
Usually, it won't be more than 100 GB at most, most likely about half, if you clean it a little bit once in a while with the Disc Cleanup Wizard and don't allocate too much space for the system restore data (10 GB max is more than enough)
If your 149 GB c:-drive is getting full, you've got some work to do.
Kees