I now hear rumors of Photoshop CS5 not being able to work properly on a Windows 8 laptop, because of some graphics glitch.
Should be no issues there. Plenty of people do run that combo successfully. If you have trouble, please post back.
My laptop is a notebook with no disc tray, so even attempting to install Photoshop CS5 will require me to purchase one, since there is no longer a way to download the trial version and simply enter my product code.
Follow the Very Important Instructions on that page first
Then click the download link to download the trial. Enter your serial number and you're done.
Those links go to the trial versions on the Adobe servers.
The trial version of Photoshop is always the Extended version.
When you enter your serial number, the installer recognises if it's a Standard or Extended version via the serial number and unlocks the relevant features.
If your serial number is rejected as invalid, you'll have to contact Adobe Customer Service