Help with recovering Outlook Express emails and contacts.?

I received an automatic upgrade from Microsoft on Friday afternoon as I was leaving the office and was told not to turn my PC off that it will shut down on its own.

Upon returning on Monday, when I turned on my PC, it took a while to load. After I had logged on, it looked like it went back to factory settings as if nothing had been done to my PC ever. There are no files sitting on my desktop, no MSN, no other shortcuts that had been sitting on my desktop. All my files are no longer in My Documents. But I have since located where they are now in the PC and was able to recover them. All the software that was installed on my PC was still there with the exception of 3 items...MSN, Booksmart, and Limewire, which I could really care less about. The more devastating one is when I opened my Outlook. It had asked me to set it up as if it were a new install. All my contacts and emails are gone. All my folders are gone. I tried looking for the *.pst file in the C:/ drive but could not locate it to reinstate it.

Can someone please help me find other ways to recover my email and contacts.

Thanks.