Hello,
I'm just going to put this here in case you might not know (the answer to your question is below) but Windows 7 went out of date in 2020. That means no more updates and it's insecure to be on Windows 7 at this point. If you understand that you're more vulnerable to viruses and malware than you would be if you were to use Windows 10 or 11, please continue.
Since Microsoft doesn't provide ISOs for Windows 7 anymore, you can use the Internet Archive. These will be user-uploaded ISOs from disks, archives of official Microsoft ISOs, etc.
You can find the HP OEM Windows 7 ISO at https://archive.org/details/Win7ProSP1HPOEM.
Hope this helps.