I downloaded the trial from Adobe just to see how it worked since I want to stay up to date. After a couple of hours downloading and installing it I clicked on it and it came up with enter the serial number checked but I checked "I want to try it for 30 days free" and after four or five minutes of grinding it informed me that it was having difficulty with my trial.
"Quit" or "Continue"
I clicked "Continue" and got the same window with enter the serialchecked but the trial was blanked out and wasn't active, you could barely see it. So, this one didn't work:
1045-0009-2130-3302-1733-9518
And this didn't work:
1) Complete installation as usual
2) Go to C:\Program Files\Adobe\Adobe Photoshop CS3\AMT
3) Delete the file called application.sif
4) Enjoy!
It said I must uninstall the program and install it again to fix the missing or corrupt file.
I threw it away. May try again some other time.
Thump