hello ,
I'm having a similar problem.
I have made a 7seg LED clock (PIC16F628 @ 4Mhz).
The clock resets when i switch on the tube light in my room.
The clock and the tube a not linked to one another in any way.
I was using a wall adapter before to power it, but even after i replaced it with a 9 volt battery, the clock still resets when i switch the tube on.
What could be the reason for this ? ? ?