OK, panic over. I found the reset switch on the bottom.
Also the 4 gig card I had was duff. I took it back to the shop and it froze their computer and it wouldn't work on their card reader. I have now replaced it with a 2 gig Kingston SD card and it is working fine. I copied all the files over to the new card in Windows and now got space to load up a few full size movies.
It's all part of the learning curve lol