Did you kep a copy of the web page as it was before you made the changes?
- If so, I suggest reverting to the old code and making and testing each change separately. That way you can isolate the problem, and hopefully solve it.
- If not, write out a thousand times "I must save my work". No, seriously, it is imperative that you set up an archive area (preferably off-line) and keep separate copies of the web site code as at each release/update. That way you can step back and isolate any problems.
Making changes to already broken code is a mugs game. By the way, why are you supporting IE7 anyway?