Car completely dead

Well I my 1998 lexus gs 400 recently got a newer and stronger battery installed because
I was having a problem with my older battery draining whenever the car is not being
driven. Had no problems with the battery since it was installed a few weeks ago. Went
grocery shopping friday with it and didn't drive it saturday or sunday. Monday afternoon I
went to the car and notice the back door wasn't closed completely and that when I try to
open the door with the remote it wasn't working. I had to open the door with the key
manually and when I got inside the car was dead. No dashboard lights, no clicking
sound, nothing came on. I assumed that since the door wasn't completely shut the
dashboard light remained on over the weekend and caused the battery to drain. After I
got a jumpstart I drove around for a bit and came back and parked the car. Now later that
night I went to the kitchen to get something to drink and looked out the window to check
on the car. I noticed that the blue light that is suppose to be blinking for the alarm wasn't
on. I tried pressing the lock button on my key to see if it makes a sound and nothing
happens. The car died again and I jumped it around 1:00 and its 9:30 now.i had a
problem of the car battery draining before but this is the fastest I have seen it drain. this
time its completely dead and I had a stronger battery installed. One thing that is puzzling
me is that I usually make sure I lock all the doors so I found that the door wasn't
completely closed strange. I don't know what is draining the battery so rapidly and why
the car is going completely dead. Nothing comes on when I turn the ignition. Not even a
clicking sound.