Alright, the only way I suspect you could do this is by installing Photoshop on a computer, then taking the installed folder and burning it onto a data CD.
However, to get this to work you will have to edit the registry. I assume that you will be able to edit the registry on the computer you want to run it using the CD. The easiest way to do this is to go to the search program under the start menu (on the machine photoshop is installed on), and look for the program file 'regedit' on the main system HDD. Open that program (it's a 32 bit windows app).
There will be a folder called HKEY_LOCAL_MACHINE, open that and then the folder 'software.' Find the registry folder called 'Adobe', click on that and then find the registry key/folder called 'Photoshop' Right click on it and export it to a file on your computer.
Close REGEDIT and include the exported registry key on the CD that you burnt Photoshop on.
When you get to the computer at work or wherever, you must open REGEDIT on that computer, then open the HKEY_LOCAL_MACHINE file, then open the SOFTWARE file. Now go up to the FILE button at the top, open and click IMPORT. Find the registry file on the CD and import it.
Now, it will say the key was successfully imported, and now you have to edit it to recognize the CD. Open the PHOTOSHOP folder and left click on the version folder. (In my case the folder name is 7.0) On the left you will see some files, and the ones with a pathway you have to edit. (ie. mine say F:\Photoshop). You wil have to change them to the drive letter when the CD is placed followed by Photoshop (for example, I would change mine to H:\Photoshop). Do this for the 'Default' and 'Application path' files by right clicking and then left clicking modify. For the PluginPath file change it to the CD drive letter and add Photoshop\Plug-Ins\ after it.
That should allow you to run it off the CD. Hope it works and hope this helps.
EDIT**** When you copy the photoshop reg key, it might not work. The reason is that it might look for the 'Adobe' file first. In that case, export the entire 'Adobe' reg key to be safe, because that will also take the photoshop reg keys with it. Then just import the 'Adobe' reg key into the software folder of REGEDIT and go from there.