I have discovered that the Kensington Expert Mouse Pro USB trackball software (MouseWorks) is interfering with the smooth operation of FS2004, especially the speed at which the dialog boxes connected with Flight Planner, Settings, etc. are accessed and changed. With the trackball installed, changes to these settings often take as long as 30-40 seconds to be implemented. Without the trackball installed, the changes are "instantaneous". Once you do get through this slow change process, however, FS2004 seems to run ok. Using the trackball to change altitude, etc., seems to be normal.The latest driver for these devices is 6.02. I have informed Kensington tech support, but have gotten no response yet.You can uninstall the software, but leave the trackball attached. It then acts as an ordinary mouse with only the two lower buttons and the trackball active.

The problem is much worse than you think.Microsoft has long contended that the Kensington drivers interfere with several things in XP. I now run my Expert Mouse trackball with the default drivers just as a regular mouse. For years installing new mouseworks software would leave strange vestages in the system.If you ever try to install a service pack upgrade for XP with the Kensington drivers installed - the upgrade will crash!I sure hope Kensington gets this fixed as I love the trackball.