If you manage to find a compatible installer or are running a slightly newer version of Photoshop on your Windows 7 machine, here are the baseline specs you should meet: Photoshop Express system requirements - Adobe Help Center

If you absolutely need an offline program, you must hunt for the legacy installer (Option 2), but be cautious about where you download it from.

This guide explores how to access Photoshop Express on older systems, the technical requirements you need to know, and the best free alternatives if the latest version won't run on your hardware.