Install Windows 7 from USB flash drive
Microsoft has released a tool to put an ISO of Windows 7 on a bootable USB drive (or on a DVD).
Windows7Hacker has an explanation on where to download this tool and how to use it : Creating Bootable Windows 7 Install USB Flash Drive or DVD Using Windows 7 USB/DVD Download Tool
Yes.
Easiest way is to mark a partition as active (although not always needed, depending on your motherboard).
Next, extract everything in the ISO to the root of the USB drive (use Winrar, 7-Zip or your favourite extraction program.).
Reboot and either change boot order in the BIOS or press whatever key it is on your motherboard to bring up the boot menu (usually F12 or Esacpe).
Choose USB drive.
Done!
Use UNetBootin to create a bootable USB flash drive with the ISO.
The software was made for creating bootable linux flash drives, but works with any bootable ISO.