I have 2 monitors.I have had an adapter placed on the system so that I can use the dual monitors for my Pro Tools program.However,I have had to replace one computer for another.It is an older model,but works very well.The tech who hooked up the system is now no where to be found.He showed me how to "toogle" with a couple of keys to open and close the screens,but I have forgotten which "keys"Is there a way that I can get this to work?

A combination with f5, I guess...
Widows or mac?

May I suggest using a keyboard/video switch, programmatically? I use both Multiplicity and KaVoom on my multi-monitor set up (two monitors on a desktop + a laptop). These programs offer easy movement between all three screens, as well as other features.

Also, a good program to provide multiple screen use especially over two computers is MaxiVista, which, as the name suggests otherwise, is NOT compatible with Windows Vista. I used this previously when all my machines were XP, and it was wonderful. I could actually use 3 monitors (2 on 1 machine, 1 on a 2nd machine) as FOUR monitors with a key toggle.

Good luck!