Go and buy a second hard drive and install it in the second hard drive bay (should be empty and not in use). Copy all files to the second hard drive after formatting and partitioning new drive to NTFS file system.
Glitches do happen when moving files (cut/paste operation), and file(s) can be lost. You can delete files on original hard drive, but then you would have no back up of your files in case of disaster. Best to back up same files to an external USB drive as well.
You can't lose what you back up, but can certainly lose them if you don't.
Without the consideration of portability which route should I go? I have an HP desktop that has run out of space on the C: drive. Most of my space has been used up by picture and video files (babies, babies, babies!) and there is just nothing left to delete. I want the current files to stay active (and not store in another location like a disc or back up location). HELP PLEASE!