How do you remove a curently running program?

if the file is in thumbnail view try changing the view .. if that dont work try changing the extention ... if its an avi file its a known bug in windows ..

you have to go to your start computer control panel and uninstall the entire program.,then restart your computer.,
good luck,.., bye,.

Boot in safe mode then delete it

To start the computer in safe mode
1. You should print these instructions before continuing. They will not be available after you shut your computer down in step 2.
2. Click Start, click Shut Down, and then, in the drop-down list, click Shut down.
3. In the Shut Down Windows dialog box, click Restart, and then click OK.
4. When you see the message Please select the operating system to start, press F8.
5. Use the arrow keys to highlight the appropriate safe mode option, and then press ENTER.
6. If you have a dual-boot or multiple-boot system, choose the installation that you need to access using the arrow keys, and then press ENTER.
Notes
• In safe mode, you have access to only basic files and drivers (mouse, monitor, keyboard, mass storage, base video, default system services, and no network connections). You can choose the Safe Mode with Networking option, which loads all of the above files and drivers and the essential services and drivers to start networking, or you can choose the Safe Mode with Command Prompt option, which is exactly the same as safe mode except that a command prompt is started instead of the graphical user interface. You can also choose Last Known Good Configuration, which starts your computer using the registry information that was saved at the last shutdown.
• Safe mode helps you diagnose problems. If a symptom does not reappear when you start in safe mode, you can eliminate the default settings and minimum device drivers as possible causes. If a newly added device or a changed driver is causing problems, you can use safe mode to remove the device or reverse the change.
• There are circumstances where safe mode will not be able to help you, such as when Windows system files that are required to start the system are corrupted or damaged. In this case, the Recovery Console may help you.
• NUM LOCK must be off before the arrow keys on the numeric keypad will function.

I would say your best bet is make sure all programs that you know of are closed, then hold down control+alt+delete (or backspace) and see if anything comes up in the applications tab. It may be kind of hard for you to go through to processes and find out which one is the right one.

sometimes when you close a program, it stays open at the bottom right hand panel of your screen (right next to the clock), check that and try closing it.
If not you could also try doing Ctrl+Alt+Delete and it will open the "Task Manager" and just look on the list the program you want to close and click on "end task", that should do it