Message- Not enough RAM to open Classic

Question

For many months we have successfully opened Classic (set for auto open on booting OSX 10.4.7).
Suddenly we get an message asking if we want to continue opening Classic with insufficient RAM (needs at least 128 megs).
But we have 768 megs of installed SDRAM, just as in the past.
Computer is Dual 800MHz Power PC G4 (OS 9.2.2 and OX 10.4.7)
768 Megs SDRAM
80 gig HD
Activity monitor shows about 400 megs of unused SDRAM when we get the insufficient RAM message while attempting to open Classic.
Can't get Classic even starting to boot.
Any help will be appreciated.
Thanks,
Tom Brewton
PowerPC G5   Mac OS X (10.4.7)  

Answer 1

Tom: See whether this excerpt from Mac Help sheds any light on your problem:
Adjusting the memory allocation for the Classic environment
Some Mac OS 9 applications make use of "temporary memory" on your hard disk in order to work faster. When you start the Classic environment, Mac OS X sets aside a temporary memory area for the use of Mac OS 9 applications. The default size of the temporary memory area is about 128 MB (less on computers with less than 128 MB of RAM). Some applications may need more than the default amount of temporary memory.
On the other hand, increasing the size of temporary memory decreases the amount of memory that's available for applications. Some Mac OS 9 applications work best if the temporary memory size is reduced to free up more memory for the application.
If you know that your application needs more than the default amount of temporary memory, or more application memory, you can change the temporary memory size in Classic preferences.
Choose Apple menu > System Preferences and click Classic.
Hold down the Option key, and then click Memory/Versions.
Click the Adjust Memory button.
Drag the memory allocation slider to the right to increase the size of temporary memory or drag it to the left to decrease it.
You can adjust the temporary memory allocation from about 48 MB to about 512 MB.
To restore the default size of the temporary memory, click Default.
Click Apply.
If the Classic environment is running, you must stop it and restart it for this setting to take effect.
IMPORTANT: Finding the optimum ratio of temporary memory and application memory can be tricky because there are many factors that affect it. It's a good idea not to change the temporary memory size unless you are confident you need to.
If you find that the temporary memory for Classic on your computer has been set to less than 128MB, that may explain the none-too-helpful error message you've been seeing when you start Classic. Perhaps resetting it to 128MB will put an end to them.