Hello. I want to comment everyone that I needed to use the backup, and it worked very well.
Backing up:
All I have done is to plug a pendrive of 16GB, tell to backup in Backtracker program, and I must say, I didn't delete the partitions with no letter from the disk (300mb, 600mb, 20gb).
Partition try #1:
I made a complete repartition of the disk (I repeat, no touching those units), but I couldn't do a clean install of OS, so I lost my windows, and also the funcionality hehe XD
I booted from the pendrive, and it restore everything, including the old partitions.
So can be quite using backtracker, it works. Just in case, keep those units.
Thanks so much for the help guys.
Regards.