Vista Home to 7 Home upgrade via digital download.

Hello people and thanks for the membership. I have an 9 yr old desktop PC with vista 32bit home premium. It has been very stable and has served me well and I use it mostly for creating laser cutter work with Corel 12, Inkscape and a few other photoshop based programs. I decided that I would upgrade to 7 home recently and bought 7 online, got a key number and link to iso. file, downloaded it, unzipped it to another folder and then ran the setup file, which i have a feeling i should not have done. I needed to abort the installation as the PC was on the "searching for updates" bit for 11 hours. Back on vista now no problem. But after reading around I have seen some people saying that the files should be transfered to DVD or USB, and installed from either. Totally unsure of this. Anyone that can shed light on my problem ?. Was not expecting trouble free upgrade but so many places suggest that it should be, but i never got past the updates.
Reasonablly tech savvy especially in matters of xyz axis, cnc operator, so not shy of computers but this has baffled me. I have 2 laptops also, one exclusively for the laser (Windows 10) and a general use (windows8)
Thanks in advance
Tony