Hi Wyowoodsmith05 ... and welcome to the forums.
Can you start a new thread (you can copy & paste your question into that). ... members generally receive notices when we reply (so they'd get notices for your replies too)
Thanks!
In the meantime, though ... Look on your Dell computer case for a sticker that shows your "product key" for Windows 7, and copy that down. (While you are looking at case stickers, you can also copy down your Dell "Service Tag" ... it can be handy). Then -- using a different, working, known-clean computer: download Windows 7 directly from Microsoft ---
Windows 7
You'll have to provide your product key on that Microsoft page to download Windows 7. If you download an ".iso" file, you can "burn" (record) that onto a DVD. But when the .iso file is "burned" onto the DVD, you must use an option such as "burn image" (this makes the DVD "bootable" [you can start the PC with it]) ... if you don't use a "burn image" option, the DVD won't work to install Windows.
If you use a Windows 10 computer to download Windows 7, all you have to do is right-click the Windows 7 .iso file and select "burn image". If you have a non-Win10 version, use a DVD burning program (most PCs have one)... look for Roxio, Nero, CyberLink, Sonic...(or just ask the owner of the computer what program they use) to create the bootable DVD using a "burn image" option.
You can then put the DVD in your Dell's DVD drive, and restart the computer ... if you are lucky, Windows 7 will show an installation screen. You will want to do a Custom install, completely removing everything else on the drive [you said that you made backups, yes?]. When done, you will have to reinstall all your programs, and restore your personal data from backups. You will likely spend quite a lot of time doing Windows Updates as well.
You might have to press a function key on your keyboard to have the Dell boot from the DVD ... on many Dells, you press down the F12 key when the Dell logo appears during system power on --- then select the CD/DVD drive from the list.
Cheers
______________________
P.S. ... you can also, if you'd like, download Windows 10 directly from Microsoft, and simply enter your Windows 7 product key ... It sounds like a "clean install" would be your likely choice. The procedure is similar to the one for Windows 7, but you would make a Windows 10 DVD rather than a Windows 7 one. Your choice! [and remember ... open a new thread :) ]