Best way to diagnose this problem is this way:
Unhook the positive terminal from the battery.
Hook up an ammeter up in between the post of the battery and the now disconnected connector. Make sure you do NOT try to start the car or turn on the stereo, etc. This will overload most ammeters.
Take a baseline reading with everything disconnected. You should see under 50 milliamperes (mA). If you're significantly higher (75 milliamperes total) then it's time to figure out what the problem is.
The usual culprits are lights not shutting off in the cabin, trunk, glove box, etc.
Next, start pulling fuses one by one until you locate what's causing the draw. You can pull and replace one at a time until you figure out which one it is.
Aftermarket stereos, alarms, and turbo timers may cause an extra drain, so if you have those on their own circuits try to isolate them as well by removing power.
If it's a fuse, then you can simply look up what's connected to that fuse in a shop manual and figure out what's getting power from that circuit. It should be easy to trace down.
Good luck! It sounds like your problem may be related to your door lock or window switch sticking and overloading the fuse for some reason. Window switches are usually on circuit breakers, so I'd suspect the door locks first.