If you mean the original Photoshop 7 from 2002, the in-program update and (optional) registration features will no longer work, but you can still download the final update to 7.0.1 (ps701up.exe or one of the regional equivalents) here:
Most modern web browsers don't support FTP, but you can simply paste that link into a Windows Explorer (file browser) address bar and it will connect, or use a browser like Pale Moon that still supports FTP, or a dedicated FTP client. I have tested applying this update under Windows 10, and it completes successfully. PS 7.01 works well under Windows 10 as long as you use partitions with <1TB free space for saving files and the scratch disk (it can, however, read files from much larger disks). It's fine on a typical laptop with a 1TB or smaller SSD.
Unfortunately, this update won't help with raw file support. In the PS7 era, the Camera Raw plugin was an extra product you had to purchase separately. This was never updated for modern cameras, and is long discontinued. You can, however, use a third party raw converter to export a tiff file that PS7 can read. Some of the camera manufacturers' own converters are free and suprisingly good, like NX Studio from Nikon, or you could look at the free versions of Capture One Express for Nikon, Sony and Fuji, or Open Source alternatives like RawTherapee and Darktable.
If you mean the later Photoshop Elements 7 rather than Photoshop 7, Adobe Camera Raw is available as a free download, but the last version that will work is 5.6: