You're welcome, wish it was more help.
If out of warranty or very careful, you can run your Thumbnail or a spudger tool around the back of the case where the rounded edge meets a flat edge and work your nail or spudger around to carefully pop the clips. Start by an opening in the case like the one for the power slider and be careful not to break the little projections or pop the switch out. I've opened mine a few times with no trouble, just be careful. Using your nail probably provides good feedback.
I'm not sure which way the battery unplugs, it may not be up from the board, but along it. Check the posts in the developer's forum too. Can't promise it'll help, but it can't hurt to try and reset it.
Lastly, it might be the image on the SDHC inside is messed up. You can find directions and get someone from the developer's section to send you an image. Of course, if it's under warranty, let Kobo replace it. They did an in-warranty replacement for me and it was impossible to tell it from a new unit, so the refurbs are either new or in pristine condition.
Use the online chat option if you can. Look around the website or maybe Google it? Online chat beats their email system by miles and miles and miles and, well you get the idea...
