The computer in question was using IE7, but I did upgrade to IE8 to see if that helped. No change.
I access the computer as well as a couple of other computers primarily using remote desktop. When using RDT, the resolution is 1440x900 on all three of these computers. Two are not experiencing the problem with the services check boxes. When I directly access the problem computer with physical monitor, the resolution is set to 1152x864 using its NVIDIA adapter. I tried changing to 1280x1024, but there was no difference in results.