It's much better to install Classic Shell, which makes it look much more like Windows 7, than installing Windows 7. It saves you the hunt for Windows 7 drivers (not sure those even exist!) and it doesn't void the warranty.
But if you're sure you want (and the owner, your work, doesn't object), I'd first buy an external DVD-drive to boot the install disk from. Then you don't have the troubles with making a bootable USB.
And then you have to tell in more detail all things you tried and how they failed.
i just got a new lapto from work HP 15-b100el sleekbook/
it came with windows 8 and updated to 8.1.
for some reason it allways crashes...and personally i hate all the EXTRA features of the win 8. i prefer the win 7 much more...
been trying to downgrade for a few days but i cant seem to do it right.. ive tried to play with the safeboot and the uefi . and also with the legacy bios...
but for some reason i cant do it right..
PLUS- it doesnt have a CD drive. so everything got to be through the USB flash (3.0)/
anyone can help with the right setup on how to make it work ??