Assuming you have either burnt the downloaded content to a CD/DVD or saved it to a USB/memory stick:
VLC can play any video/audio format known to the Internet. Make sure the audio on the computer is not muted and turned up. In lecture theatres fitted with touch screens also make sure the Source Volume is turned up to a pleasant level. If you are in a room fitted with projectors, make sure the audio is routed to the same screen where the video is shown.
Please note a downloaded internet file, which plays perfectly well on your desktop in your office or at home, may not necessarily play as well on the In House Dell PCs due to configuration differences. Owing to the myriad of video and audio codecs on the net, we recommend playing them with the VLC Media Player which is part of the standard software packet on the GATCF computers.