Please help, problems with white screen in Photoshop

[TG.]

Not sure if anyone else has found this, but occasionally when i'm using Photoshop CS3 the screen goes white and the image disappears, here's an example of what i mean, i was working on an image using the polygonal lasso tool (or any lasso tool) when i worked my way around the image, when it gets to a certain point the image disappears and the screen goes white, so i end up having to start again, but sometimes it just keeps happening, i'm sure there must be a logical explanation, any help is very much appreciated, many thanks in advance

 

[Edsport]

I get it sometimes in cs4. I just move my cursor outside the photo area then the image reappears and then i can keep going...