problem to restore a backup after harddrive replacement

As a miniumum, you need to

• ensure the client name you want to restore from is exactly as it appears in the original backup policy
• ensure the timeframe you select to restore from includes successful, non-expired backups
• ensure the policy type selected for restore matches that of the backup policy

Maurice has covered this already but backups will not be 'overwritten' but can expire if the retention period has elapsed.

As far as different versions of the file, if the timeframe you've selected encompasses more than one backup of a file (not necessarily different versions as this would depend upon the type of backup being interrogated) then there is a button within the BAR GUI that can be selected to display all backups of said file(s) - by default NB just displays the most current backup (this button is either on the left hand side if using the Windows BAR GUI or towards the right in the Java version)

If you need it:

BAR Getting Started Guide: http://www.symantec.com/business/support/index?page=content&id=DOC5146

& the rest: http://www.symantec.com/business/support/index?page=content&id=DOC5138&key=15143