The most modern version of Photoshop are all designed with the latest generation of PC in mind, which means that you will find yourself needing something new-ish, at the very least.Now the system requirements for Photoshop including the Intel Pentium 4 or higher processor, 1GB of RAM, 1GB hard disk space, graphics card that supports OpenGL 2.0 and Shader Model 3.0, and 1024x768 screen.
Minimum Pentium Core 2 Duo in there, and get around 2 GB of RAM at least. With the new monitor-ish and one mid-range graphics cards out there, you should have no problem having a PC that should last you several years from the viewpoint of photo editing.
But if you are looking at getting a new PC to edit photos, probably would be a good idea to get something a little better than that. As you can imagine, the technology will progress over the next few years and so you do not want a PC that you buy becomes obsolete in a few months, right?
