Most Western collectors do not realize that Resident Evil 2 was sold by SourceNext in a (Resident Evil 1, 2, and 3) on two DVDs. If you own this pack, the CD key is usually printed on a glossy, black-and-white sticker affixed to the back of the DVD case or inside the front cover of the manual.
If you own the disc but lost the key, use a disc-to-ISO tool like ImgBurn and then search for a "SourceNext keygen" only from a reputable, archived source like Internet Archive’s software section, and always run it in a sandboxed VM (VirtualBox).