Jetta Battery keeps draining dead (Not the alternator)

I've recently bought a 98 jetta and it was running
perfectly fine till about a week ago. I went outside
to start my car for work and i noticed it was dead...
After i got a jump it ran fine besides the fact my
stereo system was cutting out. I parked it and it
had battery life till i tried going to work the next
day... At that point i got a new battery and tested
the alternator once i got it running. My old battery
was drained down to nothing... The alternator is
fine and looks to be recently replaced. The NEW
battery lasted no longer than 24hrs and my car is
now sitting dead in my parking spot again.. I tried
to jump it the other day and now its not even jump
starting. I was thinking the voltage regulator needs
replaced? Maybe my amp for my stereo system is
drawing to much power? Maybe it's the cord/wire
connecting the alternator to the battery? Has
anyone else has similar issues that they have had
resolved? Also ive never had a German car. I've
fixed electrical **** in my 92 jeep Cherokee but
obviously they are completely different... So what
should i be looking for? Thank you very much  i
hope i get some replys because I'm pretty much
lost at this point and getting tired of seeing my
poor baby dead in the driveway.