Ok so I got my usb flash drive formatted to NTFS, I downloaded the Linux file to my computer and I downloaded Windows 7 USB/DVD download tool to put the linux os onto my pendrive. I click on the linux iso file to add to my pendrive and it says "The selected file is not a valid ISO file. Please select a valid ISO file and try again".
The linux file I downloaded is called:
It's type is "Disc Image File" and it is approximately 1 GB? So how do I get this thing onto my usb drive so that I can boot from it?
Sounds like you have made the USB stick correctly. An '07 laptop should be fine.
When you go into Bios boot menu, see if there is another option for 'HDD priority' (or the equivalent). You should see a list of HDDs. If your USB is on the list, it thinks your USB stick is a HDD. Bump it up to the top of the HDD list. Otherwise, since it recognizes your USB stick as a HDD, it skips the USB option and then goes to the first HDD on the list, which is your "real" HDD.
It is possible that your laptop does not support booting from USB. I ran into that when trying to install linux on my mother-in-law's laptop (a Toshiba about 7-8 yrs old). Try doing a google search for your laptop model and see if anyone has had this problem. In that case, your only option would be to burn linux to CD/DVD and installing from the disc.
"Ok so I got my usb flash drive formatted to NTFS, . . . F12 for boot menu> boot from USB> does not work."
If USB stick was not formatted to a linux FS before using unetbootin to load Mint onto it, this is a most
likely source of OP's problem. Learn to use SystemRescueCD, as a suggestion. Any trace of NTFS on a boot
medium can cause failure to boot linux, in my experience.