1. I was wondering if it is possible to run arch linux from a usb-like device and boot it in any computer?
2.I have a laptop installed with Win7 and i want to install arch linux but not from the same disk. If possible, i would like to use an external hard drive or SSD for arch linux. is there a way this could work?
Answers to both are well documented in the wiki and have several discussion threads on the forums. It's striking that one of the most relevant discussion threads is probably still on the first page of active threads.
Please search for your own answers instead of expecting others to hand everything to you.
(2) Works. Follow the beginners guide.