Search Function does not work in Archive Folders

Apologies if this is the wrong forum for this.

I search through my archive emails a lot. Since upgrading to Windows 7,
Outlook 2007, the search function does not seem to work in archive. It works
fine with current emails, but if I select the inbox in my archive folder, I
can be looking at an email with a particular subject, type in Search a word
from the email subject, and it comes back no results found.

I've tried indexing my .pst file and it will come back with a couple
results, but still not accurately find all the related emails.

Is this a known issue?