Maybe try inserting dvd#1, there may be an option in the setup menu to uninstall (similar to FS9).
I uninstalled FSX because I didn't like it very much and wanted to reinstall FS9.
Here's how to uninstall FSX...
Put disk 1 of FSX into CD/DVD drive and let it autorun. Look for the window (SETUP) that asks you if you want to install or uninstall. Then process with the uninstall. This will take a very long time to uninstall. Be patient. It worked for me. I'm now running FX9 again. This is a more reliable product.
I found too many bugs with FSX. Maybe my hardware can't handle FSX.