I had the same problem.   I just held down the power button until the machine turned off, because at that point, you have nothing to lose.  It has already cleared the partition for the main drive.  In my case, I just started again, booting, and then hitting F8 until it went into "repair my computer" option.   I did the very same options as before, and this time, while it stayed at 1% for nearly 10 minutes, it then went on to finish OK.
I have a Dell Studio XPS 8100. I am trying to perform a Factory Image Restore for my Windows7 using Dell DataSafe. I got through emergency backup files and now in "restore my computer" stage.  Here's what it says .... "Restore my computer Please wait... Note: You are not able to cancel this process so that the integrity of your system can be maintained. Please also do not turn off your machine during this process. Formatting your partition....(Ticked) Reinstalling your selected system backup Progress: 1% completed I left my computer the whole night turned on. After about 7 hours it still says: 1% completed Now I am afraid if I turn the computer off the computer will be unrecoverable. I had previously run PSA and no issues were found. I want to restore as I could not resolve "not responding" issues after windows boot up. How long should this take? What happens if I turn the computer off now to force stop this restore?
Dell DataSafe factory restore stuck at 1%