Okay, the first thing to do is to relax. You're going to have problems like this with any double-locking floating trem system. What you're going to have to do is to first make sure that the strings are thoroughly stretched. This is important with any guitar, but is extremely important on a guitar with a floating trem. I generally completely stretch the strings on my guitar 3 times, retuning each string after each stretching.
After you've made sure that the strings are thoroughly stretched, then you may have to adjust the spring tension. I thought this was going to be something difficult the first time I did it, but just like
string stretching it's more tedious than difficult. You shouldn't even have to take the back plate off to do this. You just get yourself a phillips head screwdriver and you adjust the two screws that control the spring tension. Try to make sure that you move the two screws together and only move them a turn at a time. It really shouldn't take much to fix the problem unless your trem is REALLY pulling up or falling down. With every adjustment of the screws, you'll have to retune and then see if the trem is back level. When I did this the first time it took me a good 40 minutes to an hour (stretching the strings and adjusting the spring tension).
When you think that you have everything level and in tune, then play the guitar for a little while and apply some light trem usage (oh, and you should have the neck unlocked for the entire duration of everything that I just said). If the guitar holds its tuning pretty well and the bridge stays nice and level, then go ahead and lock it up and it should be ready to rock. Just remember that this job is more tedious than difficult, but if you really don't feel like getting in there and doing it then just pay a professional to set it up for you. I wouldn't imagine someone charging you more than $15 for something like that.
