you said you put in a new stereo and this happened . when you put the stereo in did you use a aftermarket stereo clip or did you cut and hack the wires? also did you undo the battery?. I put a tranny in mine a couple years back i accidently bought a 96 not knowing that the wiring was diff. so i had to rewire it. i had drove it for a long time then found a head gasket leak so i changed the gasket started it up it ran i check for leaks ect ect but when i pulled a way it wouldnt move and if i did it was very little with a lot of engine rev. so i turned it off started looking found one of my battery termanels loose so i cleaned them and tightened them up and all was good. dunno if this is you're problem but i konw when it happened to me it seemed like the trany was bad or brake was froze. you said you know the brakes are froze how did you find that problem
Pugsley

Turns out to be my tranny. I lost the first and reverse band.

Idk a buddy of mine explained it lyk a band or something. But what my tranny is doing right now is that first and reverse are fighting eachother. When you put my car in reverse it wants to go foward and when you put my car in drive it just sits there.

The first thing to do is unplug the solenoid pack and see if it still does it...then if it does...loosen the trans shifter bracket and see if it is in a bind.

Beyond that...take Shiano's advise above

Lol ill have to try that before i put my new one in. I got one with 20k on it for 200 buckes. So i plan on just keeping my old one for parts and stuff.