Issue with lasso tools in Photoshop

[Ashlie]

I am having tons of problems when trying to use the lasso tools (magnetic and polygonal) to make selections in Photoshop - seems to be occuring more and more often. When I begin making the selection, everything seems fine and then about halfway through (if I can even make it that far) the whole monitor goes white and I can't see anything. All I can do is double click to end the selection process and then try to start all over. Sometimes when I start over, I can make it through and sometimes it just keeps going white partway through the selection. So a selection that should be quick an easy turns into a nightmare and I don't know what to do. Has anyone seen this before? Any ideas on what's happening and/or how I can fix it? I am a designer and I don't know too much about the inner workings of a computer.... Has anyone actually fixed this problem with success? Please help