I don't know why you got a 404 error (that means that the link you clicked on is no longer valid), but you can't get Microsoft Office with a Windows product key.
I also don't know what you did to "reset" your computer. If you restored the computer to its "factory condition," then all software that was originally installed at the factory should have been present after the procedure completed.
If you purchased and installed Office 2007 after you bought your computer, then you will have to reinstall Office 2007 using whatever media you used to install it the first time.
If you have your Office 2007 product key, you can download and reinstall Office by going here:
https://www.microsoft.com/en-us/software-download/office
If you don't have your Office product key and you purchased office from Microsoft AND you have some proof of purchase (e.g., a receipt or credit card record), Microsoft may decide to help you:
https://support.microsoft.com/en-us/contactus/
If you don't have your Office product key and you purchased office from some other vendor AND you have some proof of purchase (e.g., a receipt or credit card record), get in touch with that vendor.
If Office 2007 came pre-installed on your computer, contact your computer's manufacturer, explain what you did, and request replacement installation media and product key. Proof of purchase would be very helpful, but your computer's serial number might
be sufficient.
