OK, stick the USB stick into a port. Now reboot your computer. You need to go into the setup part (BIOS) of the computer. Normally this Somewhere in there is a boot order list. You need to make sure that USB is listed before the harddrive. I wish I could give you better instructions, but they change depending on the version of BIOS you have. Once you are in BIOS there are instructions either along the bottom or the bottom right corner telling you haw to maneuver and change settings.
You can also just try rebooting to the USB and see if it is already set that way.
You need to be there during the first part of the bootup, because it will ask you what you want to do, and you want to Run Ubuntu From This USB. It should already be selected and all you should have to do is hit enter.
Once you get Ubuntu started, getting around is very similar to windows. Go up along the taskbar on the top and then over to the left and click on Places, then click on Computer.
Now depending on how many drives you have, you may have multiple drives show up. Go to the one that matches the size of the drive where the two files are located. Now you can go thru the directory, just as you would in windows to the files. Then right click on them and select Move to Trash. once both are deleted click “Go” in the toolbar, then select Trash. Simply click the “Empty Trash”, your Trash folder will be empty. Now you can remove the USB drive, and then in the upper right corner, click the power button and select reboot.
Now windows will startup, and you can see if the files are gone.