Starts fine one day, battery seems dead the next

Check main 20A fuse under right side cover.

one of the power wire leads to one of the turnsignals is pinched to ground

the kick stand safety switch could be bad.check it out

check out your side stand safety switch

If the bike ran fine prior to putting it in storage and all you did was drain the fuel and disconnect the battery, its likely moisture ( condensation) developed in the carbs while it sat. this type of thing happens when fuel is drained. Your best bet is to remove the carbs and clean the jets. Its my opinion and experience to put fresh fuel in a bike along with (stable) fuel treatment prior to storing them. With the stable added to the fuel, the fuel will hold good for about 1 year.. Replacing the battery and starting them and letting them warm up to operating temp monthly while in storage is always a good idea..
I hope this helps..

If it has only sat for a week, then your not in any real trouble. As long as your seals are good and no water has leaked into the gas tank, then it should be able to start right up.

Here ya' go mate...this site has the whole bike in sections, exploded views and parts lists....go for it!
Cheers.

http://www.cmsnl.com/suzuki-gz250-2002-usa_model16123/partslist/