Assuming you are using Microsoft's built-in defrag tool, it doesn't look at other drives or the memory but how much free space is on the drive that it can use and needs 15% I think in order to run. What you will have to do is move some data from one drive to the other to free up enough to do the defrag, or at least that is what I've done in the past.
Hi, i have a sony vaio bought in 2001. It had only 256 ram and a little mbs hard drive. I use windows xp. Recently i was getting low disk space messages and then i tried to run my defragger and it said i didnt have enough room to run it. So i bought 256 more ram and put it in, and now have 512 ram. Then i bought a second internal hard drive and designated it as "slave"-it was for 120gb's. They both show up in my system info so it seems the os knows their there. But, when i tried to run my defrag again-it said i didnt have enough space on my c drive again. All that new room and my computer doesnt seem to be using it! Im i missing something here? Do i need to tell it to use it? I just dont get it. arggg!!! Lizzie