Easiest method is to run this app, choose Windows 7 in the dropdown menu, load ISO, it formats and writes the flash stick in minutes: Universal USB Installer – Easy as 1 2 3
Boot under USB, Removable or HD's.
If install stalls again, make sure you have latest BIOS version. If so, reset the CMOS: Clear CMOS - 3 Ways to Clear the CMOS - Reset BIOS
While in BIOS setup, set SATA controller to AHCI. Unplug all other HD's and peripherals.
Adapt steps here for getting a perfect install: Reinstalling Windows 7