what image are you using ? (date)
2012-03-23 (as in this thread). I needed to upgrade it because I bricked the system when running the shipped 2012-03-08, after trying to cure an EPG problem (didn't handle BST change too well!). I deleted the EPG.dat file and the system would no longer boot up!
you have to unplug the HDD to get the box to boot ? otherwise it green screens ?
Not always, Rat. Just if the system has seemed to freeze up, or has become unresponsive, and hence needs a forced shutdown and restart (using power button on the box). Used to happen quite a bit on the original 2912-03-08 image, but the box is now a LOT more stable on 2012-03-23 so it's been worth it so far.