Ipod apps wont open PLEASE HELP?

I have an ipod 2nd generation, i have had no problem with my ipod but suddenly the other day i noticed one of my apps wouldnt open. like id click it and it would blink and go out of it, then another app and now i cant open any of my apps they open for a sec then go out of it, its really annoying and i dont understand whats wrong i tried reset all setting didnt work just annoyed me more because i took away my background and moved things around which isnt a big deal but it didnt help anything whatsoever ive tried charging it restarting it its been 2 days and only spread worse, also note my ipod is jail broken and i have apps on there that cannot be removed i dont know how to get them back someone else jail broke it. is there anyway to fix this without deleting apps ive watched a few videos on youtube for how to fix this but they all delete your apps, also what caused this?