92 Mazda MPV Starter and Electrical Problems

Hi all - I'm having a lot of problems with my 92 Mazda MPV. About a year ago, it mysteriously failed to start (after sitting in my garage overnight). The battery was ok, but nothing happened when I turned the key. I left the car sitting in the garage for a year (I've been away) and would now like to get it running again. However, it appears that there is an electrical problem now. I'm not getting any power to the car (the lights don't work). I tried hooking up jumper cables and am still not getting any power. I've also checked the cable connections and the fuses, and they seem ok (one of the fuses, labeled "all" is slightly discolored, but not broken). Does anybody have any ideas what might be going on? Thanks! If you had a minor electrical problem a year ago, letting the car sit can lead to major electrical problems. Corrosion sets in. Don't expect anyone to guess right on this one.

Start by removing and thoroughly cleaning the battery connections and ground. Then you had better take out your voltmeter and test for voltage at critical points. And test that discolored fuse.