Screen goes and stays White

Hi,

I  like to look at my work against a white background and I set it up in LR that way so that in D or E, when I double click L, that's what happens - my image appears against a pristine white background. Except in F mode of course, in which case the background remains ... black - unfortunately for me.

I have noticed the problem is more prevalent in D mode than in E. But I may be wrong.

In the past few days, when I double click L, the screen flutters to white and often requires another L click or going back or forward one image to perform as required; but too often, stays white. In which case I reboot LR to get back on track. I have a sense that my processor is struggling - am I right? Or is it something else? I keep all my images in one library - which is the way I need it; could that be the cause? BTW, I implemented some setting adjustments suggested by Julieanne Kost to make the system more efficient a week ago.

I am showing my work to someone today and it would be nice if LR functioned smoothly.

Thanks a lot,

Raphael