I'm not an expert by any means, but if it's giving you the OS not found info then your mother board is probably fine. Make sure that your Pendrive comes first in the boot order. You may be getting that info because your computer is looking for an operating system in a disabled hard drive.
Here's one more USB creator to use as a last ditch effort: http://www.pendrivelinux.com/univers...easy-as-1-2-3/
That's what I used, I never even attempted to use unetbootin.
If you really think its your mother board, check out ebay. There's a lot of good computer parts to be found there, & it's where I got 90% of the parts for my IBM/Lenovo Laptop.