Photoshop CS has stopped working

I have been using Photoshop CS (v. 8) for some years on my eMac with OS X 10.4.11. A few days ago I got into some trouble unconnected with Photoshop, involving an inability to delete a large file I had been downloading or to empty the Trash, and had to switch ythe computer off with the mains switch. Now Photoshop will not work any more — what it does is to open as far asthe initial screen with the title and details of the developers, etc., and then shut down again. I tried the following measures in succession, each time verifying that Photoshop still did not work.

1. I re-installed Photoshop (over the original one).

2. I trashed all Photoshop preference files.

3. I ran DiskWarrior to re-organize everything on my hard disk (I do that every few weeks anyway) and used the Mac's Disk Utility to verify the startup disk and to repair disk permissions.

4. I trashed Photoshop and every file associated with it and then re-installed it from scratch.

4. I used Onyx to reset the LaunchServices Database.

5. I reset PRAM (whatever that is; at the moment I think my computer needs a hearse, not a pram).

6. I reset Open Firmware.

7. I checked most of my other major applications and ensured that they are all working. By the way, I have not installed anything new that I can think of since Photoshop was working perfectly well.

If anyone can suggest anything else I could try, I should be immensely grateful. I use Photoshop a great deal and at present have a lot of photos waiting to be editrd. I ought to add that Photoshop CS (i.e. v. 8) is the only version that, in combination with particular versions of the Adobe RAW plug-in and Adobe DNG Converter, allows me to process camera RAW files from my up-to-date cameras on my relatively ancient computer and operating system.