I tried this a while ago and got USB error messages so gave up. I have tried again today and got to the same point again. Downloaded the R112653.EXE file from Dell and followed the instructions - backup, power on, USB connect, etc and eventually get a screen on the PC telling me there is a USB problem and a X51 that is stuck.
Forgot to note the exact message but it hinges on the USB connection. No problems with Activesync so I thought that all my USB drivers were OK. Just to eliminate the PC I also tried it from my Laptop and had the same problem.
No problems getting back to where I was so I'm not looking for advice on that.
Has anyone else had this problem and how did they solve it?