You should discover Windows 7 doesn't natively support boot and running from USB. There are other OSes that will boot and run from USB.
I have had an server hardware problem (Motherboard), I know i can get over this by just replacing it. (Hard disk still ok)
Just been curious whether i can boot this hard disk on another machine by using an enclosure with it and connecting using the usb port.
I tried this by taking the usb boot option in the boot menu option, but to no avail.
Am i doing something wrong.