1988 Volvo 760 battery drain

Hi, I have a 1988 volvo 760 turbo with 169000 miles. I had the alternator rebuilt in August of 08 because all of my dash light kept coming on and then the battery would be dead when I tried to start the car. It ran ok for about 2 weeks then the dash lights started coming on again. I took it back to the person who changed the alternator and he said that it was not the alternator but something electrical.
I have had to keep taking off the battery cable in order for it to start when I need to go again which is getting to be a pain. I took it to a volvo repair man and he put in a new battery, however the next day it was dead again. I have had people pull all the fuses we could find to check those but that does not seem to be the problem. I also am having a problem (which may not be related) with the fuel gauge where it does not show any gas in the car and then will go up to where it should be.
I am looking for some help as to what else should be checked to see if we can find the draw which seems to be quite strong to kill a brand new battery.
Thank you for any help you can give me.