Problems.. 98 Jetta doesn't start after rain, power loss, hesitation, no radio

Hi...
This started after recent snow and rain. 98 Jetta sounded like it would start but didnt fire up.. Towed it to mechanic. He did a tune up. Next time it rained same problem.. Engine didn't crank up although the starter made the cranking noise. When the weather dried up, it started again.
Soon battery started draining and recently the check engine light came on and radio wouldn't start. Took the battery to Autozone. They were able to recharge it. So battery isn't the issue. Reinstalled the battery. But the check engine still on, radio still off and power loss, hesitation and engine dying when idling at traffic lights, continues.
Today it rained and engine fails to crank up.. AGAIN..

Will seriously appreciate if any veteren Jetta holders can give any insights or think I should dump this car. I don't want to. Shes been nice to me.

As a general place to start, look to see if you have water getting into the electrical connections of a fuse box or relay box under the hood. Blow it out with compressed air.