Hi,

You can press and hold the power button for 5 seconds to turn the computer off. Disconnect the power cord, monitor, keyboard, mouse and other external devices (desktop computer) or disconnect the AC Adapter, battery and any external devices ( for portable computer). Press and hold the power button for 10-15 seconds. Reconnect the cables. Restart PC, enter safe mode and perform a system restore. Here is the link on how to perform System Restore. System Restore does not affect personal files, such as email messages, documents, or photos. It only affects software application and settings. The programs that you have uninstalled may appear.

Also, what programs were you trying to uninstall?

Hope this helps.
Please reply if you have any further questions.

Thanks and Regards,
Manpreet C