I have an old Sony Vaio sitting on my desk. It doesn't even have a network jack. Not even a modem jack. The battery is shot so it has to be plugged in 247 to even work. Unplugging the power to it acts the same as a desktop - instantly shuts off.

But, it has a VGA plug. I'm running a 22 inch LCD widescreen via DVI, and it has an output for VGA too... I'm wondering, if I plug in a VGA cable from my monitor to the old Sony, can I get it to run as a 2nd screen?