Look for Dell Command | Power Manager instead of Power Manager Lite. Type Programs & Features onto [Cortana] search box, and then look for it. If you don't find it there, type Settings onto search box, click System, Apps & Features, click on it and then uninstall.
Go to start- settings-system-Power&Sleep. From there change the settings to meet your criteria to keep the system from sleeping. Click Additional Power Settings at the bottom. Select each option on the left and change the settings on the right that meet your criteria. Do this for each section.