If your exchange data was on another partition, you should be able to get your emails back. Reinstall the OS and exchange. Make sure to update to the same service pack level that you were at before it crashed, and backup your existing database in case something else happens.
Once re-installed, open the Exchange system manager. Navigate to and expand your storage group. Right click and dismount your mailbox store. Right click on the mailbox store and click on properties. Go to the database tab and change the location of the Exchange database and streaming database to the your existing database files on the other partition. Remount the mailbox store. Do the same for your public folders. If your database files did not get corrupted, you should be fine.