Help! My baby doesn’t start anymore!?

Hello guys, I’m new here. Have a problem with my Audi 80 B4. When I got in this morning he didn’t jump any more! So short to my baby! He was converted to Euro 2 in about 2005. Since then you have to let it down briefly when you start it. Probably hangs together with the retrofitting. Is an automatic. I inherited the car from my opi in April of this year, so it has been maintained accordingly and regularly for inspection in the workshop. He just dropped 137,000. So now to the description of my problem: As already said I got in this morning, started the ignition and wanted to start it. All I heard was a click and it happened nothing more. Then did I charge the autimatics, whether it really stands on P (since my husband was still on the road yesterday with the car). But was also the case. I could really cry, because this car is the most important thing for me. Did one of you know what I can check out to find out what it is?