computer module blowing a fuse?

My 99 jetta has been possessed for about a year.  At first the battery would not hold a charge, so I paid for a new battery.  The dealer replaced it twice! Car just kept killing it.  In August I replaced the alternator, figuring that was killing the battery.  The new alternator wires are looking burned and it wont start.  I had a mechanic try to hook up diagnostic computer to it but it could not find the car computer.  A search of the fuses showed fuse 29 burnt.  The only thing I can find on that fuse is the computer module.  When I replaced the fuse it snapped.  What could short out on the module?  Could the battery guys, or the alternator guy possibly done something to short out the computer?  I could take it back to them to repair.
 
It was running fine after the new alternator, I just drove it home one day after work and it wouldn't start again.  I hate to get it towed and then pay over a grand for a new module to find out this could be something common. (or simple)  Any help is greatly appreciated.

I thought I would follow up on my post.  I had the car towed back to the garage that replaced the alternator and they did extensive diagnostics on it (by elimination) and found a small crack in the coil causing a short on fuse 29 which is on the same fuse link as the main computer module.  The module itself was fine and protected by the snapping fuse. After replacing the coil and recharging the battery the car is back to running perfectly.
 
Since 1973 I have only had 4 cars. 1971 vw squareback, 1981 diesel rabbit, 1985 Jetta and now my 1999 Jetta. Although the price of parts, if bought new, gets expensive all the vehicles have served me well. The key is excellent maintenance and care, and finding a competant mechanic with patience.  Don't always assume the dealer knows all.  I would have paid for a new module and still would have had a problem because of the coil. The coil problem did not show up on the initial computer diagnostics.