Unfortunately, that does not solve my problem: I am using CS3 - all hints direct to CS4, which I do NOT have. However, I tried swichting on the use of multiprocessor as described in your link, but it still uses only 4 gb.
The information in that FAQ entry is still mostly valid for After Effects CS3, especially the important point: After Effects CS3 is a 32-bit application, so each process can only see and use a theoretical maximum of 4GB of RAM. However, with Render Multiple Frames Simultaneously multiprocesing, After Effects spawns additional processes that can each use its own few GB of RAM.
Here's the page in After Effects CS3 Help about the Render Multiple Frames Simultaneously multiprocessing feature:
Don't be so quick to dismiss information about CS4 as being irrelevant to CS3 (and vice versa). Most things don't change from one version to the next, so information written for one version is usually still good for the next. (If you're ever unsure, you can use this decoder ring page to see what's changed from CS3 to CS4.)
Microsoft does have an official Windows 7 Support Forum located here http://tinyurl.com/9fhdl5 . It is supported by product specialists as well as engineers and support teams. You may want to also check the threads available there for additional feedback.
Microsoft Windows Client Team
This question is not about Windows 7. It's about After Effects and how much RAM it can see and use. Please don't distract people with extraneous links to the Microsoft site when you don't understand the issue being discussed.