How to install Adobe Photoshop CS5
I can't find the question there but in regards to Adobe Photoshop cs5 installation, this application is easy to install. It would just take several minutes. Just make sure that your computer meets its minimum requirements. And by the way, MAC OS X and Windows has different requirements.
Regarding the memory, it would be better if you have at least 2gb of free memory or more since Photshop 5 requires 1gb of memory and there are other programs are using the computer's memory as well. There should also be a plenty of storage space on your hard drive.
Also check if you have the appropriate Videocard and support OpenGL.
That needs at least 256 Mb RAM.
You can find the steps on how to install Adobe Photoshop cs5 here: