You bring up some excellent thoughts.

I currently, and have for quite a while, had two hard disks in the PC, plus I have an external disk.

The first disk (disk 0) has partitions C and E, the second has one partition (S). I do back up the files from both C and E to S on a regular basis, and before doing any major changes. I only have the operating system files on the C partition. Most of my software is portable, so it is easily backed up.

I believe my problems resulting from the second OS load (64-bit) was that it did not erase/format the C drive, an option I was used to with the XP loads. Live and learn!

I’ll do a complete backup before running DBAN. Hopefully the next Avast install will be less troublesome.