non starter, need help!

I have a 1994 MR2 t bar and about 8 weeks ago i parked it on my drive and have not driven it since (been travelling). Anyway on my return i attempted to start the vehicle and nothing! obviously i tought a dead battery as it has been standing for some time.

I spent 20 minutes charging it off a donor car (brand new vehicle) and still nothing, however the headlights, hazard lights, instrument panal lights all work fine.

Any ideas as to what it could be, could it just a be that the batttery is old and no longer holding its charge? or does it seem to be more serious?

Any help would be much appreciated

Thanks

has your car alarm imobilised the starter while you've been busy charging? is it manual or auto? if auto is it in park?