HELP!!! How to Use Virtual Drive?

A Virtual CD-ROM Drive?

Daemon Tools. Google it.

How big is it

I don't know. I assume around 3 or 4 MB.

can it actually play PS iso files?

it can mount them.

One thread is enough. Stop making multiple threads to ask about the same thing. First PS-exes, now this... It's annoying and confusing, and it will actually work agaisn't you because you'll probably end with the same answers on all the threads, and if you need further clarification, you'll have to ask on each and every one of them. Just stop it, please.