Dell Inspiron updated - can I reinstall with Win 7

I have a laptop that is horribly slow since forced onto Windows 10 (half an hour awaiting updates every time I boot up). I do have a retail Windows 7 Ultimate available (not oem) and wondered if I can reformat this laptop and then reinstall with Win 7. If so, are there any cautions other than 7 isn't being a current version. I run 7 successfully on desktop but would appreciate being able to use the laptop after I upgrade the desktop. Thanks.

laptop is Inspiron 1547
i5 quad-core 1.7ghz
8gb ram
1 T hdd

Witch OS came with the Inspiron 1547?
To install Win 7, on BIOS you must turn off secure boot, fast boot and enable CSM (Compatible System Mode).

The desktop will not have Windows. With the issues of 10 I'm jumping ship...I have spent more time in the last three years trying to make things work than finishing tasks...so much so that I just give up.

The Laptop I want to put 7 on started life out as Win8 and was supposed to have had a 7 downgrade option which of course Dell renigged on. I can then give it to my son who can't afford one on his own. He's used to 7 so I think it will be a better fit. I cannot use it because the sys requirements for Adobe CC are higher even though it's only a year old.

I will check out the bios first, and will thank both of you for the great responses! The only thing bad about not going to another windows box will be missing this forum. You're all the best!

LafnSu