Y axis motor issues

First off, sorry for the long post and back story...

So I've had my 1.0 for a little while now, bought it used locally. After printing a built in test print from the original firmware to ensure that the printer works fine after I got it home, I promptly loaded Repetier to it, and after some dialing in it's been printing great ever since then, probably 2 dozen prints or so on my own ABS spool. Still can't seem to get prints to center in the bed with the new firmware, but that's another subject all together...

Yesterday I tried to start a print, a simple tool tray that I modeled, and upon the initial movement to the prints starting location, the nozzle struck the screw in the back right corner that holds the build plate down. This little jolt threw off my Y axis belt tension (which I didn't notice at first), but about 5 minutes into the print it started missing Y movements. So I stopped the print, noticed the main Y axis drive belt that runs on the Y axis motor was loose, so I popped the side off and adjusted it out to take out the slack. Put it back together, moved it around manually, and all seemed well.

I modified my G-code so that my print's start movement would go to the X and Y axis first before moving to the Z starting point so that it avoided the screw head the second time around... and that all worked great. I monitored and let the first 3 or 4 layers print and all looked like it was doing well. The print had 2 1/2 hours to go, so I went into town and let it be. Not the first time I've done that, and it's never given me issues before.

Well when I came back to it, I was greeted with a messy wall of ABS from left to right on the top of the print...

The Z axis had completely stopped moving and the machine basically just moved left to right for the rest of the print, extruding ABS into a solid thick wall lol.

I tried to check the axis movements and noticed that again, the Y axis main belt that the Y axis stepper motor directly drives was loose as can be... So I'm thinking that belt has stretched and I need to at least replace it...

But then I tried to manually reach up and turn the drive on the Y axis motor, and it felt locked up solid! So I pulled the motor out (mounting bracket still attached to it), and sure enough it was locked up, wouldn't budge...

Well, here's another crazy thing. I took the 4 screws out and removed the mounting bracket from it, then miraculously the darn thing was free and can spin just fine now... so I'm at a loss on that...

Should I take a chance with this temperamental motor, reinstall it and see how long it lasts? I do think I need to replace the belt on it at least... Should I just get a new motor and belt and not even bother trying this "sketchy" motor and probably stretched belt?

I know parts are hard to find for these (original parts anyway), so what options do I have for the Y axis motor and the small drive belt that's on it?

Thanks!