Windows came down on their own??

[ARModen]

I'd check that microswitch in the center of the windshield. The window's lowering means the car thinks you are putting the top down. Your roof not going down would be the same issue.

The Alarm control module is located under the passenger seat on a UK model. Your weird idle and the rest sounds like an electrical problem. I'd check battery terminals for good contact and see if your ignition switch got wet/corroded in the process.