how do i connect my wireless desktop to my HDTV
do I need to buy some electronic part
Depends on your desktop? Is it relatively new? Does it have an HDMI out? If it does, simply run an HDMI cable, autodetect monitors, set it as the primary, and then disconnect the current monitor if you'd like. Simple as that. If you don't have an HDMI out, honestly, it would be more trouble than it is worth, get a new desktop.