a little help please..ignition, fuel or electrical problem?

[Ramathorn]

okay well yesterday i picked up a 95 disco from a private party and drove it home (160 miles or so). when i got home i started to clean it up a little bit and replaced the headlight bulbs with some new piaa gt-x's.

well this morning i went out to go start my new rig up and nothing. it sounds like it wants to crank over but then nothing. i tried to start it for about 10 minutes before i got upset and pulled the battery connectors off and checked to see what the charge was.well after me trying to start it for 10 minutes with nothing i think i drained it down a bit since my charger read about 25%. so i set it on the charger and took my bike out to go do my running around. got home it read a full charge so i tossed it back in same problem. (i got it back on the charger again now)

when i first try to start it it sounds like it wants to start but then time after time of me trying to crank it over it gets weaker.

the guy i got it from said that its been having a start up issue the past few weeks. he told me that it was something to do with one of the injectors. the previous owner actually showed me what it was because when i went to go test drive it, it actually diddnt start. when he went to start it up he just bliped the throttle ever so lightly and thats what helped get it to start (i tried with no such luck today).

input on what my problem might be or anymore pointers on trouble shooting my problem would be greatly appreciated.