HI, well its a complicated question. You CAN run some programs etc from a usb. But I doubt you can run a whole O/s. And jury rigging it to boot to an external drive and have it pretend its the main d rive is .. the first time I have heard anyone attempt this * chuckles* But ten points for you for thinking out of the box *G*
If I were you, I would
1) set the bios to boot from USB and have a SCANDISK utility on it so that you can fix your main disk. I have seen that work MANY times., YOu need to search up bootable utilities SCANDISK
YOu may have to know how to get around in basic dos commands to do that
depending on what utils you get,
2) find a friend who has a multi external hard drive adapter, ($20) take it to him have HIS computer boot it up as a external drive, and run scandisk on it, then you can put it back into yours.
3) go to a teck, tell him y ou want him to do #2 for you
4) If you can boot at all.. power on and keep pressing F11. This will give you the option to restore your laptop to factory LOADED condition,
Booting to F keys.,, safe modes, restore and now apparently pressing TAB while your booting up ( just keep repeatedly pushing the key) Im told now gives you a LIST of options,
Bottom line,, Research your make and model for TECHNICAL specifications.
every computer has a user manual and a teck manual, These keys will be listed there,
But find a way to scandisk in dos to save your hard drive or F11 on boot to completely restore ( you loose everything, and everything is brand new loaded)
When it comes to stuff like this http://www.computing.net/ is the absolute best.
Sincerely Sue