It's IMPOSSIBLE to lose your contacts, Calender etc if you have your Outlook (PST) backed up or you use Exchange server. Your mobile is a COPY of your data and not the MASTER!!!
If your PC Failed, how have you recovered your Office Outlook (not Outlook Express rubbish) email?
WM phones is designed to sync with your Exchange server, or manually to your Office Outlook. It will sync new contacts and Calender entries that you add to your phone over GPRS, Wi-Fi if your using Exchange, or by USB or Bluetooth if your using conventional pop3 email in MS Office Outlook.
You can't blame Active Sync or WMDC for not backing up your PST data