From 7 to 10, and back to 7, not by choice

My desktop Lenovo H415 with an AMD A6 was originally unsuccessfully upgrade to W10 on the first day it was available but the system was unusable and I reverted back to 7 and I waited for Treashold2 but the problems still existed. Now I want to do a fresh install of 7 since my original installation is over three years old. I don't have a 7 installation disk and since my s/n is now embedded into my eufi (I'm told), am I going to have a problem activating a new installation of 7? I'll have to wait until I upgrade my hardware (maybe next year) before I use W10 on my desktop.
Len

If your PC came from the Manufacturer with Windows 7 it should have a COA sticker on it with your license key for that PC.
If you special ordered the PC with a downgrade to Win 7, and Win 8.x was the default OS it won't have a COA sticker.
It's my understanding the license (s/n) was not embedded into the BIOS until Win 8.
Win 7 and earlier OS's use the COA sticker.
If you have a readable Win 7 COA you can clean install Win 7 and activate it.

Were you running Win 10 as an Upgrade install, or did you do a clean install of Win 10 ?
Many people report issues with the upgrade install, but problems are often solved by doing a clean install.

Here are examples of a COA sticker.

Well I first did an upgrade install of W10, but the second time I used a new hard drive and a clean install of 10 but the problem persisted. Another problem is that I can no longer get into setup. I restart and hold F1 or F12 and the computer ignores my input and just opens in windows. I guess that is my most pressing problem since without the ability to boot from a DVD or a USB, how can I do anything. I appreciate your help, thanks.
Len

Tried to get into setup by using DEL, F1, F2, F10, F11 and F12, nothing worked. Is there an emergency way to enter the setup utility? I need to do a fresh install of Windows 7 but I have no way of doing that without changing the boot order.
Len

lenberman said:

Well I first did an upgrade install of W10, but the second time I used a new hard drive and a clean install of 10 but the problem persisted. Another problem is that I can no longer get into setup. I restart and hold F1 or F12 and the computer ignores my input and just opens in windows. I guess that is my most pressing problem since without the ability to boot from a DVD or a USB, how can I do anything. I appreciate your help, thanks.
Len

Some things you could try:

- Try repeatedly tapping the F key while the PC is booting, don't hold it down.

- Try a different USB port for the keyboard.

- Disconnect the HD that has Windows. Then Windows won't be able to start and it might force it to let you into BIOS setup.

- Do a BIOS reset by removing the CMOS battery for at least 10 seconds, then replace it.
A possible issue with this approach is if the PC was originally designed to be sold with Win 8.x installed and Lenovo downgraded it to Win 7, they might have changed some BIOS settings from the factory default. Things such as Secure Boot, Fast Start, etc. and you might need to play around with settings to figure out what is needed for Win 7. You would definitely need to set the date/time correctly.

I purchased this computer in late 2011 or early 2012, I think that was before Windows 8 was available. Is there a way to find a file that lets me know when I first used this computer. Thanks for your suggestions, I will try them.
Len

Open a Command Prompt (CMD) and enter this command:

systeminfo | find "Original Install Date"