AVZ, Thank you so much for your assistance. I was very much in hopes that it would solve my problem, but, alas, no.
My only options were 59p Hz and 60p Hz. It was already set on 59. When I changed the cable this time I noticed a message window that says "Input out of range. Change settings to 1680x1050 60Hz." It was already set on 1680x1050, and changing to 60Hz made no difference. Very frustrating!