Why would I have low compression in my 1997 ford escort 2.0 low compression when the timing belt was replaced 1000 miles ago and it will not start now but the belt is right on the marks?

You've realigned the marks, but did you check which piston stroke? The marks will align in two instances, top dead center on the compression stroke, and top dead center of the exhaust stroke. I'd bet money that you've aligned the timing marks to TDC exhaust stroke. That would explain 0 compression in all cylinders. Rotate your crank shaft by itself (leave the camshaft where it is) 360 degrees (one full turn) and you should then by aligned to TDC compression stroke, as it is supposed to be.