Re: To be fair...
Photoshop 7 has always given me grief with installing on Win7 64 bit -
It's been a while since I had to re-install my trusty genuine copy of PS7, but ISTR the 7.01 update is necessary for installation on x64.
It still has a problem with larger hard drives; if free space is beyond some large-by-2002-standards amount, PS7 complains that the drive is full. The workaround is to save to a different drive. As mentioned above... it's 13 years old, so we can overlook its quirks!
As for Win10, I posted my thoughts on it a couple weeks ago over on the forums. It's better than 8, in the same way that the Flu is better than Ebola, but it's far too privacy-invasive for my liking. Just about every one of the capabilities in 10 requires a Microsoft account and upload of all your contacts/history/data to the cloud. No thanks.