I have been having the same problem.
My suggestion, try to get ur phone charged to 100% connect to a laptop/PC and take whatever backup you can. The recovery tool will wipe old data.
When I had initially installed the WP10 preview. I could not get screen for any thing. The screen was black/blank for anything (app, slide down notification etc) no apps would start. I could not take pictures, I could not change Internet etc.
Then I did the Windows recovery tool restore. It wiped my old data but installed all my apps from the one drive apps backup.
I still have the blank screen problem. When I hit the home/start button none of the tiles come. Occasionally I have seen that once I have 100% charge, the tiles come back. anything less than 100 and the tiles cannot be seen. The phone is practically useless. I cannot make calls nor can I use any apps. I could not take pictures too. I can however search and browse!!
At the time of writing, I do not see any tiles. Not even the notification area tiles. It is very frustrating. I just charged my phone(charge is 92%) and I am slowly getting back my tiles. I am planning to go back to the original WP8.1 status.
Hope some of the experience details help.