We have five computers in our office. All but one are syncing the calendar in outlook just fine, back and forth, as is a mobile device. Each of these machines uses .ost data files. The one computer that isn't syncing with the rest is using .pst files. I've tried to change it over, but when I go to add a new data file, it only gives me two options, both of which are .pst. From what I've read, this format can't support syncing for updating the calendar through our microsoft exchange account. And solutions or ideas?

Is it possible that this is caused by Outlook not being connected to Exchange? And if so, how do I remedy that problem to remedy the former?

Yes, very possible. You just need to make sure the user has the Exchange Server service in their Outlook profile. What version of Outlook are you using? Does this user have an Exchange mailbox?

I believe it's 2007, but I can't check for sure, as if you check out my other post from this morning, you'll see that outlook is just gone from that computer now... As for the exchange email, as far as I know, the whole office runs on one.