clean install of windows 7 so i can upgrade to windows 10 for free?

[that1man]

i just built a new computer and it has no cd drive. how can i use my windows 7 disc to make a bootable usb drive so i can install using my key and then take advantage of the free windows 10 upgrade?
i still have my old computer so do i deactivate windows 7 and install on new computer then do the upgrade?

whats the best way to get windows 7 on a thumb drive?

 

[photonboy]

You don't have to install Windows 7 first.

1) Use MS Media creation tool to burn a W10 install USB: https://www.microsoft.com/en-ca/software-download/windows10

2) Start installation

3) Insert W7 key when prompted for a key

*Wait...
To be clear, you can't move Windows 7 to a new machine if it's already been activated. you have to buy a new copy of Windows 10 in that case. So if that applies to you do the same as above but buy a W10 key (can do it after install).

You can also try looking for a cheap W7 or W8.1 key at Amazon etc ($45 or less) and use that for your upgrade.

 

[_Blink]

+1 to photonboy.

If it's on the same computer, you can use your windows 7 licence key for a free upgrade to windows 10.
Proof: http://windows.microsoft.com/en-za/windows-10/activation-in-windows-10
Reason: 'digital entitlement'

And yeah, only if it's on the same pc, otherwise you'll have to get a new w7 or w10 licence.
Proof: http://answers.microsoft.com/en-us/windows/forum/windows_7-windows_install/can-i-install-windows-7-on-more-than-one-computer/98446282-a524-4ec0-a45d-3ebefb3ed799?auth=1

All you need to do is upgrade to windows 10, then use your w7 licence key.