Yes, it still hangs, every time I exit AfterEffects. Didn't do this on the other system, but it happens every time on the new Win7 system.
Here's what Windows tells me when I CTRL+ALT+DEL it...
A problem caused this program to stop interacting with Windows.
Problem Event Name: AppHangB1
Application Name: AfterFX.exe
Application Version: 18.104.22.168
Application Timestamp: 478c63c2
Hang Signature: 9211
Hang Type: 0
OS Version: 6.1.7600.2.0.0.768.3
Locale ID: 4105
Additional Hang Signature 1: 9211893d34005b04e83fad9e5588e523
Additional Hang Signature 2: 8afb
Additional Hang Signature 3: 8afbc2ba10ab47c80f2930d55195c48e
Additional Hang Signature 4: 9211
Additional Hang Signature 5: 9211893d34005b04e83fad9e5588e523
Additional Hang Signature 6: 8afb
Additional Hang Signature 7: 8afbc2ba10ab47c80f2930d55195c48e
Is the solution that Adobe apparently found (and included in their CS4 update) going to be made available to CS3 users?
Are there any settings I could/should change?
After Effects CS3 came out long before Windows 7 did. Here's an FAQ list about Windows 7 support.
Especially notable is this part:
Will earlier versions of the Creative Suite family products and components support Windows 7?
Adobe Creative Suite 4 and Creative Suite 3 solutions were included in our testing efforts. While older Adobe and Macromedia applications may install and run on Windows 7, they were designed, tested, and released to the public several years before this new operating system became available and have not been tested. Older versions of Adobe software will unfortunately not be updated to support the shipping editions of Windows 7, since our engineering and test teams focus on more current configurations. For known issues regarding the running of Creative Suite products and components under Windows 7, see the Knowledgebase article.