A program? maybe.
A windows update? Probabaly not.
If you want to uninstall an appliction that has no uninstall program and it is not listed in the Add/Remove applet of Control Panel
(or that uninstall doesn't work), then just delete the directory/files.
Then open regedit and drill down to:

HKEY_LOCAL_MACHINE\SOFTWARE\ and HKEY_CURRENT_USER\SOFTWARE

locating the applications entry and delete them.

Use Explorer to to remove the entries from the Start Menu in either
%windir%\Profiles\All Users\Start Menu\Programs\ and/or
%windir%\Profiles\YourId\Start Menu\Programs\

If there is an entry in the Add/Remove list, edit:

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Uninstall

locate the entry and delete it. If the app has a service, edit:

HKEY_LOCAL_MACHINE\System\CurrentControlSet\Services

and scroll down till you locate it. Then delete it.

If this app starts automatically and there is no entry in the StartUp folder(s), then use Regedt32 to edit:

HKEY_CURRENT_USER\Software\Microsoft\Windows NT\CurrentVersion\Windows

load REG_SZ and
run REG_SZ

Remove the offending value and reboot.