Although it is possible to achieve this, I usually highly discourage it because of the risk involved with such a setup. It is called a spanning volume. It allows the hard drives to work in unison to achieve an accumulated total of hard drive space.
The reason I discourage it is because with this setup, if one drive fails, you lose everything. Typically with a low recovery rate. Needless to say, it is risky.
Your best bet is to resolve the issue of why your computer cannot locate the files you're trying to move.
Edited by t3chie, 01 August 2010 - 04:51 AM.