VGA just won't work that far away.
25 ft is fine for VGA. You might get a bit of noise starting to appear if you run it by power cables and such like, but it should work.
That said, I really wouldn't recommend it. In this day and age there's really no reason to either - why not just use two PCs? Or if you don't want to do that, use a thin client and connect to the other remotely as suggested above?