Back up with Fulldisk encryption (Truecrypt)

Situation :

I made a full c-drive backup (with Acronis & Shadowprotect desktop) from a running system, encrypted with full disk encryption (Truecrypt 6.2) (so unencrypted backups) .


The backups are stored on an external USB drive.

1)What will happen to my system when I restore the backups on a running system ?

(for example like when i messed up some settings, and i want to restore back quickly)

2) what will happen if i need to restore BEFORE booting with a bootable CD.

(for example a virus infection that makes the system unbootable).

Do i need to encrypt my whole C-drive again (everytime) ? (long process) ?

Or is it in some way directly encrypted when i boot up ?

Or does it just messes up my PC and makes it unbootable ?

Is it better to make backups (with boot CD) from the encrypted volume ?

Is this possibell ?

Does this makes restoring much easier ?

Thanks beforehand !