1990 s4 electrical problems
 

I have 2 electrical problems with my 1990 s4. I've owned the car about 1 yr & if it sits for more than 3 or 4 days the battery goes dead. when I drive it everyday I have no problems whatsoever with the electrical system. I've had the battery tested at SEARS & was told it's okay. Was wondering if this is a somewhat common problem.
the second problem : the windows & sunroof suddenly stopped working. since the three switches are tied together, I checked them ( after finding no problem with fuse or relay ) & the 3 switches are getting current.
I was hoping to solve this on my own. It's quite a problem because the a/c doesn't work - needs new compressor & more. Has anyone had similar trouble? Thanks