I could not find a way to force garbage  collection, but there is a
similar problem discussed here:
discuss.fogcreek.com/.../?cmd=show&ixPost=72832
They mentioned using DoEvents and looking at memory  usage in the
task monitor. There are also MemoryTotal, MemoryFree, and MemoryUsed
properties you can look at.

Off hand, your app does not seem like enough load to crash VBA. Are
you using external functions? One of them may be the culprit. Or you
may have created something recursive by mistake.

I tried using the DoEvents and it doesn't seem
to be working. I don't use any external functions, and I don't think
that I have anything recursive. I may be wrong about that last one.
Just as further background, the Mem Usage continually grows and the
only way to clean it out is the actually close the Excel application
itself. Not just the file. If Excel is still open, it still takes up
the same amount of memory.

Do you think you might be able to check out some items if I send you
the main sections of code? If not no worries. Any other ideas would
be helpful.

Just wanted to update this thread for future reference if anybody runs
into the same issue. It's actually tied to a bug that Excel has with
ADO queries. The article describes how to work around it.