Try doing a Ctl-Alt-Del to see if it is a current running process, if so then end the process.
If it does not show up there you can try the following. Download and install
Spybot. Open Spybot, then click on Mode in the top menu bar and select Advanced Mode. In the manu bar on the left selct Tools then System Startup. Uncheck anything that you don't recognise or don't require to start when Windows boots up. Close Spybot and reboot the system. Try your Windows Update then.