Hmmm.....random crashing (on any computer I'm assuming) and no way to pinpoint a specific event causing the crash.......
I believe you said you compacted and repaired the mdb (as well as debug/compile the code)
I have someone at work who's testing MSAccess mdb's with Windows 7 and hasn't come across any major problems. It seems like you're pretty sure it's something with the Windows 7 os box?
1. the DisableShiftkey worries me. It's not a technique I prefer myself. This is one area I might look at for problems.
2. possibly a setting in the windows 7 environment (doubtful) Are the MSAccess versions different?
3. Import all the objects (forms, queries, modules, reports, etc..) into a brand new mdb, debug/compile compact/repair.
4. Make sure you have a default printer assigned to the computer. I've had many mysterios crashes only to find out there was no default printer.
5. Your application sounds like it's got a lot of non-typical MSAccess coding in it. Eliminating things like the Outlook code etc... might help but I'm just guessing here (unless it's a simple docmd.sendobject command.)
Have you tried create a separate mdb (using Windows 7) and testing it ONLY on windows 7?
It seems to me though that some code (maybe the Filter code) or other menu-type commands or possibly the dynamic linking is problematic, especially if both os versions seem to be using it. There are still a lot of non-typical functions (such as outlook code, disableshiftkey, dynamic linking etc...) that have not been fully tested on windows 7 (even though it shouldn't matter). Sorry - that's not much help. It's very possible that windows 7 is interpreting something different than the other os (although this problem usually is between MSAccess versions where you have some users on 2007 and others on 2003.)
You may also want to start with a new mdb and slowly import certain forms/tables and test. If that tests ok, import a few more forms and 1 or 2 of the API type modules and test. It's a slow process but it helps for the future.
Here's a link which may or may not be helpful:
DBForums Code Bank
DBForums Code Bank
There just some basic checklist items on speeding things up (tips and what to look for) but hopefully one of the items will trigger something to look at.