Bad choice, for both Ram and PSU.
borrow the dvd drive from a friend.
this should help: 1. Microsoft Store Online
2. Installing Windows 7 From USB Drive 3 Steps Easy Process
but make sure your motherboard is capable of booting off a USB stick or this will not work
this should help: 1. Microsoft Store Online
2. Installing Windows 7 From USB Drive 3 Steps Easy Process
but make sure your motherboard is capable of booting off a USB stick or this will not work