You can get the Splashtop app. It links your iPad to your computer over wi-fi. I can watch flash videos with it. Couple of dollars I believe (it's been awhile).
There are others that can link over the Internet. Say, you're at a hotel with wifi service in another city, you can link to your computer at home and control it. Go to the hulu website and watch the office. Logmein, the one I'm thinking of, costs around 20 dollars. There may be others like it. Not sure.
But for around the house and yard (ever how large your wifi signal is) or free wifi, I recommend splashtop.
Note, I have Bose computer speakers that disables the internal computer speaker controls and I have to unplug them to get sound to come over to the iPad. So, if you have an aftermarket speakers (if your speaker icon on your desktop is crossed out) disable them by unplugging.
Note also, when the iPad is controlling the computer, somebody else can not use the computer - the iPad is in control.
Don't know if you have multiple screens on your desktop...