R26, A bit of advice for a few issues

Hi

there’s a few things I need to sort and would not mind a bit of guidance.

1st thing is my xenon’s. Headlight stopped working the other day so I replaced the bulb. It come on to start with but now doesn’t, so now I’m going to replace the ballast.
When i go online i get 2 types of ballast come up one that looks square and one rectangle type which has two connectors on. Does anyone now which one is correct for an r26.

2. I think I have water getting in the boot lid and I have a feeling this is causing my alarm to go off. I reckon it’s from the boot as when I changed a number plate light fitting it was quite corroded and wet. Has anyone had this and what the best solution

3. Drivers side electric window is very temperamental. I’ve done all the reset thing and still only works when it feels like it. I’d also like some advice on a solution for this.
Thanks