Impossoble installe Photoshop 5.0 on new PC with Windows 8.1

If you cannot get Photoshop 5 to install using compatibility mode then chances are you will need to get a new version of Photoshop to go with your new machine.

if that's really ps 5 you might be able to use compatibility mode to install but that's a long shot because i don't think there's a compatible os option.

better would be to upgrade to ps cc.  the most economical option is a special $9.99/mo photography program, http://www.adobe.com/products/photoshop/buying-guide.html