The first step in removing XWindows Dock is to go to the control panel and click on the programs link, which is a blue square with two vertical lines. Click on that link and choose add/remove programs. When you are done, click ok. The next step is to go to start menu and type in "control x settings". This will bring up a dialog box where you should select "run" and enter. Once you are done, click ok. The last step is to close all programs. When you are done, restart your computer to put everything back to normal.
The final step is to search for the program that you want to uninstall. For most programs you will not need to download a program to remove it, because the program will just unload the files that were used while the application was active. However if you want to remove XWindows Dock from your start menu, then you will need to download a program called XoftSpy to remove the files that are in there. Download this program to get rid of the program forever and start using a new start menu. The steps above were how to uninstall XWindows Dock, the same steps that you need to do to remove any virus that might be on your windows 8 machine.