Database Recovery

Is the instance back up? This is your first and foremost issue (if not) because you won't be able to do anything until that is resolved. Any errors in the event viewer? What have you tried already? If you try to restart the service what happens?

At some point, you will also need to determine when the server went down as that will tell you when you'll need to restore to.

Also, have you verified that your backups are valid? Have you restored them somewhere else?

First step: Can the instance be brought back up? Is it something as simple as someone switching off the server, or has something gone more seriously wrong?

If you can't bring the server back online (within a reasonable timeframe), then you need to recover your backups to a new server/instance. First restore the full backup, then all the transaction log backups in the order that they were taken. If you can bring the old server up for long enough, try generating a tail-log backup - http://msdn.microsoft.com/en-us/library/ms179314.aspx - and restore that on your new server to bring everything back to the most recently committed transactional state.

no the instance is not up yet, when I try to connect the instance, I got the error: that network drives are inaccesible. And this might be due to the datafiles residing over there..... What can be done?? Also, the backups are good and tested on other server......

If the instance is not running then you need to locate it in the Services on the server and start it

1. I think the first thing to check is service ? Is SQL Server Service running ?
2. If service is running,try to connect to master database ?
3. If service does not start,restore master database from last backup ? http://msdn.microsoft.com/en-us/library/ms190679.aspx
4. Restart the service in multiuser environment and restore the user databases.