FSX and WindowBlinds

I am posting this in the hope that it may prevent somebody from having the hours of frustration I have just experienced! Having got FSX performing really well recently, after SP2 and DX10 mode - fps between 15 and 40 normally, and between 40 and 100 in the UK VFR scenery - I suddenly found that fps had reduced to between 7 and 15. I tried all sliders to the left, all sliders to the right - the result was the same 7-15 fps. I had the same anti-virus programme running (Kaspersky), I had defragmented the hard drive, got rid of junk files, optimized settings etc etc etc - nothing worked, and I could not think of any other programmes I had added that might be causing a conflict and slowing things down. I have been running WindowBlinds for ages, with FSX exempt from WB skinning, and this was all still in place unchanged. I eventually discovered that, although WindowBlinds was not skinning FSX, particular skins were causing the slow-down. Change to another skin, and up went the fps to their previous levels. No more problems, and another FSX performance problem that turned out to be nothing to do with FSX!As I say, I hope this is of help to someone.Jeremy