I have a windows 7 pro 64bit license. Upgraded to windows 10. Id like to do a clean install, from my googling I see that I can freely do a clean windows 10 install as long as I keep my mobo. Is this true?
Would I be screwed when I eventually upgrade thus new mobo cpu etc?
I'm not sure about retail licenses. Not sure if Microsoft limits the license for the Win10 upgrade to the hardware where installed. It would make sense, even so, since they are providing the new OS to you free of charge. I say this because it's only possible that your retail license would become "OEM" once you install a Win10 with the Win 7 product key.
I personally put off updating to Windows 10, even thinking that I'd never do it with these existing machines. I discovered that you can download either the ISO file or the bootable USB Win10 install, and then make a dual-boot system by:
1) Upgrading as an overlay to the existing Win 7 -- keeping Win 7 operability but merging the newest OS with the old as a VHD boot volume. Don't do it this way: it is too much extra trouble to get the old Win 7 files deleted or removed.
2) Use a tool like Acronis Disk Director or True-Image to create a bootable CD/DVD version of the drive utility software. Booting up with the utility disc in the DVD device, you can shrink the existing partition and volume for the Win 7, leaving unallocated drive space. Then, run the downloaded USB or disc created from ISO and install Win10 on this unallocated space. You will then automatically have a dual-boot system with both Win 7 and Win 10. Obviously, you would want to leave the Win7 volume with space to spare for new files or programs, so it depends on how much free space you try to maintain on the boot volume.
3) You can add another HDD or SSD to the system, then install Win10 onto the new disk. It will STILL create a dual boot system, and both OS's will use the same 100MB system-reserved area on the original disk with the Win 7 installation. So there may eventually be a problem in deleting the Win 7 -- but with any attempt to MOVE the Win10 to the original boot drive. Some advice in this forum points to a need to do a simple repair with the Win10 install disc, and it will correct itself.
So it would seem that method (1) will give you grief for eventually removing Win7 -- which you might want to avoid. Method (2) is the best of the three, because after using MSCONFIG and its "Boot" tab to delete the Win 7 OS volume, you can then use your disk utility to expand the Win10 volume -- keeping the 100MB "system-reserved."
Method (3) is also easier than Method (1) as far as prospective removal of Win7 is eventually in the cards for you, but has the uncertainty about needing the repair and making it successful.
Of course, disks are so big these days, you might not wish to bother uninstalling Win 7, even if you begin to like Win 10 more and more.