Well if its been sitting for 7 years you will definitely need a new battery, might not even be able to jump the old one. You can try charging it on an over night charger (or at least a 3 hr one).
Is it that it won't start or that there is no juice? In other words is it doing anything at all when you turn the key? First thing to do is think of all the components in the starting system; battery, starter, spark plugs (you can test to see if you are getting spark very easily), plug wires, ignition, etc. Also check fuses and relays. Oh yeah!! Bad gas, make sure to siphon out all bad gas, don't use it, and change the oil, very important! Let us know what happens. Best of luck my friend.
