I bought 2 Dell E6410 laptops. They had W7 pro on them. I upgraded to W10 on the 1st one with an old W10 ISO/USB, and it hung and crashed and couldn't recover anything, so I installed 7 with loader on it. On the 2nd laptop, I DLed a new version of W10 ISO, made USB, and it installed & activated and all is good. These originally had Vista on them, so the needed key is gone.... I upgraded the 1st one to W10, but it isn't activated.... Any suggestions?