LEL 2013 / London - Edinburgh - London Audax

It's a 4GB Sandisk MicroSDHC card with loads of space, so I'd like to think it's not that, but you never know. Oddly, although the PC would suddenly recognise the device with the card removed, it still wouldn't switch on without it - hence the factory reset - so it's possible there were two problems. In theory the card shouldn't have been in use anyway except maybe holding the maps... :S

I've heard of SD cards causing issues with phones so I would always be suspicious of them until proven otherwise. Often people buy cheap ones though and/or don't format them properly for the device they're intended for. Lots of variables though.