you can either end tree for Explorer.exe in the task manager under the Processes tab, then go to File>Run and click browse, find the file manually and try deleting it then, then you go back to File>Run and type in Explorer and hit Ok to get your desktop showing again.
but rather than try to do so and waste your time, you might as well restart the computer in safe mode by restarting the computer and keep hittin the F8 key on the keyboard, a menu will load that will say something to similar to "Start Safe-Mode" with another one saying "safe-mode with command prompt", but you need to choose the first one instead of the command prompt one, the computer will start up lookin like the graphics are shitty but this is because in safe mode the computer loads only the basic components that are needed to start windows and in return will not load the file you cannot delete . So go find the file and manually delete it or Run your antivirus again. Then restart normally.
a third way you can try to do so is by running Hijackthis which will remove things from startup , then try to remove it.
you should go with the second option i posted tho, everything else was to fill u in on some things.