At some point this was working, but now it is not. I am using Windows 7 x64 and Office 2010 (32-bit.) Windows 7 Search will find email in my .pst and .ost files, however, I cannot open them from the Search Results window. I've checked the registry key indicated in this post:
http://social.technet.microsoft.com/Forums/en/w7itproui/thread/2689d78a-4871-451f-b9c4-719eb2bcd2e2
In registry editor, navigate to [HKEY_LOCAL_MACHINE\Software\Classes\mapi]
On the right panel, right click >> New >> String Value >> Enter "ShellFolder"
Then once the key is created, right click on "ShellFolder" >> Modify> > Enter "{89D83576-6BD1-4c86-9454-BEB04E94C819}" without quotes.
Is the value different for Office 2010? If so, what is it? I've never had Office 2007 on this machine. It's a new build with Office 2010 freshly installed.
If you don't have outlook installed, then you need to use 3rd party tools to see the contents. One such software can be found at : http://www.recoverytoolbox.com/open_pst_file.html.
Alternately if you have Outlook and it's still not able to open the .PST files, try SCANPST to see if they are corrupted and have it fixed.