I have simiar, though not exactly the same problem

My 7 year old Dell sever in a small office setting is starting to spit out:
"F:\ is not accessible. Not enough server storage available process the command" when accessing it from multiple on site machines.

The HD is SCSI at 10 GB and I have 1.6 GB of space left. Note that I was down to about 800 mb and took a lot off of it, but still get the same mesage sporadically. When I go to the server keyboard directly, I have no problem getting into it. I then delete any small file from it, and the problem goes away for a few days, usually. I am running Windows 2000 Professional on it.

Are there any suggestions, or is it really time to look for a new server (I had planned doing this later in the year).