unfortunately MS DOS (Command Prompt) won't recognize a portable drive (USB)
If your hard disk is partitionned (ie: C:, D:, E: , ...) then you can simply format C: after moving all your stuff from the C: to D: (or E: or F: etc..) by using the different commands of the command prompt (copy/paste/move etc..) here is a list of them :
Otherwise, it seems there is a way to back up to external drives whiles in Command Prompt but I am not sure it works... Anyway here is the link I found :
About two days ago I was running an update for my ipod software in itunes, and noticed that Windows was also installing an update. Then my laptop accidentally over heated( it had been a problem in the past) and I waited for it to cool down.
When i went to reboot it later, I was shocked to find out it would NOT reboot. It gets to the screen with that little bar with the green square moving from left to right, the screen normally right before the welcome screen, and then it goes black. It takes me to a screen announcing that my computer has failed to start and that I should run a system restore to fix it.
System restore does nothing, but in Diagnostics I notice that it says the root problem is a bad patch, or a failed patch. I have tried System Restore, taking it back even to the 16 of october, and it didnt work. I tried to boot it in Safe Mode, and no luck. I tried going back to last known good configuration, and no luck. I tried a restore disc, and repairing it through that and no luck.
I can open up notepad in command prompt, and see that all my files are clearly still there. Is there anyway to fix this, and if not, can I rescue my files and save them somehow on a portable drive before I reformat my laptop?