Windows 7 system Image

I am pretty religious about data backup, offsite, triplicate drives, fire safes etc but overlooked the actual Windows installation as W7 is so robust, I have not had to reinstall it in all the years since the PC was put together.

So got caught out the other day when it truly broke and had to reinstall, a few long evenings! not a bad thing really as it gave me an opportunity to update everything, leave off the dross and upgrade from 32 to 64 bit (a licence code works for either, who knew? :cool:)

Now we are all back in business I need to make some baseline backups, it looks like that is built in with the 'make system image function' in Win7.

So to the questions, can the image be restored from say a USB external hard drive plugged in? do we know if sufficient support is loaded after a boot from the install disk to read it?

Its too much for DVD's and there is a second hard drive in the PC that it looks like it might be able to use an image file on, but I really want to hedge against a catastrophic virus infection that would be on all drives on board.

Thanks.