[Nexus S Q&A, Help & Troubleshooting] Androyed:
Let me try to explain as comprehensively as possible what happened before I couldn't start my Nexus S again.

Until yesterday, I was running an older CM9 Nightly, together with the Matrix CFS kernel (18.0) and an older reloadedICS mod. Everything was running fine. Well, except for the fact that every time I rebooted, it took 2 or 3 times before it actually started. So 2 or 3 times, while rebooting, my Nexus S rebooted again, or just crashed so that I'd have to pull out the battery. But when my Nexus S finally started, it worked fine. I still had the occasional crash, but everything worked.

Yesterday, I decided it was time for a new nightly. So I downloaded the CM9 nightly from 7 april, the latest gapps, the newest matrix CFS kernel (18.5), and the Reloaded ICS 1.9b2 mod. Before I flashed everything, I wiped cache/dalvik cache, as always. I did flash everything at the same time though.

I didn't like the new icons in the statusbar from the latest Reloaded ICS mod, so I downloaded a different version of the Reloaded ICS 1.9b2 mod that someone had uploaded, with the different icons. That also worked fine. Every icon changed, except for the battery icon.

I used my Nexus S for the day. I listened music, browsed the web, whatsapped with some people... It worked fine. Then I went and watched some TV. After that I went to bed, and I noticed the battery of my Nexus S was empty. Since I wanted to check my mail/facebook before I went to sleep, I put my Nexus S in the charger. I started it, that worked fine. It said the battery had 0% on the statusbar, and because of the new battery icon from the Reloaded ICS mod, you can't see anymore if your Nexus S is charging. But it started, so I guess that's what counts.

So I started facebook (in the browser). Halfway loading, my Nexus S crashed. I experienced crashes before, certainly with CM9 nightlies, so I wasn't really surprised. I pulled out the battery, because the power button wasn't working (again, wasn't surprised, that's normal with that kind of crash).

And that's when things went wrong. My Nexus S wouldn't start again. I tried starting it in fastboot mode. Didn't work.... I put it in the charger for the night, but the charge icon (the white battery icon) didn't show up on the screen. And the next day (today), it still didn't start. I know someone who also has a Nexus S, so I tried his battery. Didn't work. I tried his charger. Didn't work. But when he tried MY battery and charger in HIS Nexus S, it DID work! Well, except for the fact that his Nexus S is still trying to boot up, after half an hour...

So that's two Nexus S's dead. One that won't even charge anymore. The other at least shows signs of life. I have no idea how this is possible. Clearly it has something to do with pulling out batteries, since his Nexus S wouldn't start anymore after he pulled out the battery when it was still turned on, and my Nexus S wouldn't start anymore after I pulled out the battery when it crashed.

By the way, my friend's Nexus S is not rooted. He is using stock ICS.

Thanks a lot in advance!

Edit; i also noticed that my battery was going down exceptionally quick after the 7 april nightly. I don't know if this is relevant.