I can't tell ya how many times I've found a cement truck causing trouble in a GameBoy...

also in reply to noobstar, i've taken off the back light and tried to see if it works without it and the problem persisted, i've cleaned and searched the pcb as much as i can for any damage or drippy soldered or covered connections. nothing seems out of place, i think i may have to just try fiddling with the ribbon cable and see if i can get it working.

http://www.youtube.com/watch?v=nxMEvqI1lOs here's the buttons in action, if you want i can take pictures of both the pcb's as well.

Most of my modding problems involve those last two.

I've never opened a GB in my life, hell never even owned one, but I did study electronics for a bit. My guesses would be:
-ribbon controller is misaligned indeed.
-new hardware you put in is making a connection somewhere, somehow, but that is unlikely for a screen mod.
-case is a bit too tight with the new hardware, pcb bends when pressing something, making a connection
-a rogue piece of metal made it into the case when you closed it back...a staple, a bit of wire, a broadsword, a cement truck... etc

In order:
-Open it up again, look at everything and make sure it's all according to plan.
-Remove the ribbon, clean it with a cotton swap and a bit of alcohol (for the swab... not for you)
-Look in the ribbon socket see if there's anything in there that shouldn't be, and blow in it to make sure all the dust and gremlins are out.
-Clean the dpad/button top pcb with rubbing alcohol or circuit cleaner.
-Make sure everything is dry like bones first
-Insert the ribbon like you were performing brain surgery, make sure its perfectly aligned.
-Close it back up, and tighten the screw only as much as it needs to hold it together without rattle. Overscrewing can bend the case and what's in it sometimes.

If that doesn't work, try removing you mod if it's not too hard and then see if that fixes it. If it does, then at least you'll know the problem isn't with the GB itself but rather in the mod, or its installation process.

give me a second i'll put up a video

can you also post the way the buttons are working now?

like, if LEFT became UP, or whatever...

or, if some are dead.  that will help troubleshoot as well.

i could have possibly plugged or unplugged the ribbon cable when it was on but not that i'm aware of, it would have been unintentional if i did. Is there someway i could fix the alignment?

did you perhaps unplug/plug-in the ribbon cable when the console was powered on?

or, perhaps it went in misaligned?

Recently i purchased a backlight from nonfinite electronics. I successfully put the back light in and soldered it in place and everything and it was looking great. However to my dismay when i put my whole gameboy back together and turned it on it started up fine but then i discover that the d-pad now somehow links itself it every other button. I'll try to explain this better, what i mean is that when i press the left button it starts moving left but also presses the a button at the same time and etc. I've taken the thing apart and nothing looks incorrectly soldered. i've even tried changing where the back light was soldered too and it doesn't seem to change much. People say the ribbon cable could possibly be damaged but i'm not certain because i've seen images of a damaged cable and mine looks perfectly fine in comparison. i'm just wondering if you possibly know what the problem may be? if you want pictures of it i can give you some.