reinstall os x lion 10.7

I lost my entire Macintosh HD disk.

I have the backup from Time Machine.

I tried to start the computer from my old Mac OS X installer disk but it does not work.

I have an old OS X 10.6.8 version in another external drive which I am using to start the Mac Pro.

I tried to use the Time Machine to recover but it does not work.

Any suggestion please.