I think you maybe mixed up the 'mount' part. 'mount' does not mean 'restore'.
A full backup.tib of C: will contain all the files - OS, programs and your personal documents - an exact copy of everything as it was on the date you made the full backup.tib, all compressed into an image file.
In the case of a hard drive failure. If you had taken a full backup of C: and it made a .tib file you restore to a new drive by booting from the Acronis boot dvd/cd. You need to have the other hard drive with the .tib on it attached and switched on and you need the Acronis boot dvd/cd in the tray before you start up the pc. Then you follow the on screen prompts. (you may have to alter the boot order in bios setup)
When you have finished and reboot the pc (don't forget to remove the dvd/cd or it will boot back into Acronis - but you can always choose the 'boot into windows' option on the menu if you forgot) the new drive becomes C: and you are up and running (all files will be what your original C: was on the date you made the .tib file)
Although it also depends on your OS, if you have W7 with the separate 100mb boot system reserved partition you would need that as well as C:
If you want to restore the C: on your present hard drive then you have a choice of booting from the Acronis boot dvd/cd or starting Acronis from within Windows.
What partitions have you got on your pc?
I find it handy to have another spare hard drive to which I have restored a backup .tib then in case of problems I can just swap the hard drives over and be back in business in a few minutes. It is also a handy way of checking the backup .tib works okay. I could clone instead of restoring but the way I do it I still have a spare hard drive that I can if need be delete contents and use for something else with the knowledge that I have a backup.tib that works. (note to self, could do with another hard drive come next birthday..)
Having said that, I don't keep all of my personal documents on C: I have another 2 internal drives and an external for those files.