Strobe and Nav light problem

Suddenly, all my aircraft with strobe and nav lights show them as a box of light as opposed to a small point.

What have I done/what can I do?

I am running FSX gold without acceleration on Win10. It happens with both MSfsx aircraft and downloaded aircraft.

You should have SP1 and SP2 installed.

Your problem is either in the aircraft cfg or effects folder.

Presumably you mean FSX SP1 and SP2? Is it safe to put these in on Win10?

Yes it's safe, you'll see you have more power.
They use all cores of your CPU.
Without them you only use one.