If your computer says it's out of memory, it just means that a part of the machine is filled to capacity. Memory — known in computer dweeb circles as RAM (random-access memory, pronounced ram, like the goat) — enables your computer to run programs. Photoshop needs lots of RAM — version 6 requires a minimum of 96MB and prefers to have even more. If you can't launch Photoshop because of a memory error, you have three options:

• Free up RAM by quitting all other programs that are currently running.
• Restart your computer by choosing the Shut Down command from the Windows Start menu and then choosing the Restart the Computer option. After your computer restarts, try to launch Photoshop again. (On a Mac, restart the computer by choosing Special, Restart at the Finder and try to launch Photoshop after the Finder reappears.)
• Buy and install more RAM.

If you've never tried to upgrade the RAM in your machine, seek out expert advice from your local computer guru.