I just wanted to add a bit of additional information. The wireless card that I pulled out of the MSI CR620 was a half mini PCI card. The 4965AGN that I put in is a mini card and had to be installed in the other slot. Would that possibly be part of the issue?
OK, based on feedback in other forums, it looks like I'll probably return the 4965AGN and get a half mini wireless PCIe card. Based on my experience with this card so far, I'm not sure that I'll get another Intel card. They seem to be problematic so far.