Anres is correct.
When I was using ESET NOD32 v. 2.7, it had TWO START-UPS, not one.
There was one "invisible" protection *.exe that was launched as part of the boot sequence BEFORE log-on,
and another GUI *.exe that was launched after log-on.
They should be launched with special options from special parts of Windows,
and dragging a short-cut into the start-up folder will not achieve perfection
(though it may give an appearance that all is well)
When I upgraded from a USB modem to a Router/Modem the system was badly affected.
Previously the ESET GUI would try to get virus signature updates,
and would wait for the USB modem to sign on with my ISP before it could download and scan.
With an "Always On" connection ESET did not wait,
and it consumed CPU cycles and delayed other parts of the Windows Start-up sequence.
The delays prevented "Safely Remove", "Volume", "Power" etc. icons from getting into notification tray.
I removed ESET GUI from the log-on start-up, and added it to my own start-up script.
This delayed ESET GUI until the rest of Windows was running, and "Volume" etc. was in notification tray.
The ESET help-desk told me a special option switch that was needed when launching the GUI.
I did not alter start-up of the "protection" *.exe, but that too may have needed a option switch.
If you did a total removal and re-installation you should be O.K.,
otherwise get advise from ESET.
If you standardise upon one set of protection for all computers,
You may find it less confusing,
and a group licence for 3 machines should be cheaper than 3 different licences
Alan