Had same issue - but then it cleared up
I had similar problems a couple of days after I bought mine, where it would constantly crash and I literally thought I'd killed it.
In the end, after leaving it (switched off) overnight, and doing several hard reset, it all came good and started working properly again. It almost seemed like it had an overheating issue with being on constantly, or possibly an issue with the number of things I'd queued up for downloading in the background. (I'd been using it while connected to the USB so it was always charging, and as it was new, even when I wasn't actively using it, it was downloading lots of stuff in the background over my painfully slow Thai internet connection.)
Since then, it's been fine. Great for watching videos streamed over uPnP from my network, until today actually where it's started playing movies too fast. (i.e. similar to watching movies on x4 fast forward).