COA win 7 came with my computer on a flash

I purchased a new computer off of eBay. IT came with windows 7 pro on a flash drive. How would I find out if this windows 7 pro on this flash drive is OK I mean could code be put on a install that Norton or other paid virus protections would not be able to detect ? Is their a utility out there that is able to check up on these things. You know it seams the only way to be 100 percent sure that your win 7 is actually safe is to buy it new from a reputable source and then you STILL don not know if its been hacked with. I mean if you look at it in a very factual way.

Hi Don.

assuming the "new" comp does NOT have an OS installed

Use the tool and the Iso provided earlier to install W7, stay away from the Stick.
The >> ONLY<< thing you require is the key

The key provides the licence to run W7, irrelevant of where its purchased or how/where its installed.

On another computer
download the tool and the Iso to your >> desktop <<

run the tool - then import the Iso - you now have a bootable usb with W7 on it.

on NEW computer change the Bios to boot from USB first, reboot to reset

plug in USB turn on comp -- press any key to load.
Set up your drive most people use 2 partitions
dont forget to reset Bios for HDD first

SKIP the key input on install let it update, there's a 30 day grace period.

As for your key enter it tomorrow, as a quick key check google the last 3 blocks - multiple hits = bad news
If it comes back clean input it and for further confirmation run this tool, copy/paste the output
http://go.microsoft.com/fwlink/?LinkID=52012
,

Roy