I would audit the system using OTL
, or another auditing application to capture information from the system.
Remove all private information from the log file; licenses, user info, personal info, anything you wouldn't want to just outright give me. Then PM me the log file.
To me it sounds like one of the following is occuring.
1. A custom app you are using in d7 during service work, or dSS during maintenance, is installing crapware on these systems.
2. You have a network infection. (Also could be a USB drive like previously mentioned)
If you create a new user account, and install dSS with admin privileges, and run manual maintenance through dSS, what happens?
I would also like to suggest installing dSS on a clean VM, running Process Monitor so that you can capture installation data. Run dSS, and like you have stated, let it set for a while and see what happens. If and when the My PC Backup shows it's ugly face, you should have some details as to how it got there.