Dual monitor not working

Hey everyone,

My house-mate just gave me his old TV he used to use as a dual monitor, I plugged it into my computer using a HDMI cable however I can't seem to get it to work, i've googled and asked various sources and can't find what i'm doing wrong, however this is my first time attempting dual monitors. My first monitor is connected via VGA and the second HDMI, so I changed it to both VGA but that doesn't seem to work either. Any help would be greatly appreciated.

P.S. Sorry if this thread isn't in the correct place or I missed out any information needed etc, its my first time on these forums, have a nice day :)

Thanks for the help Kari, but I think i've just found the problem, the TV works when I change it to the VGA/PC setting and plug it into where my monitor was plugged in on my pc, so it looks like I can only have one monitor at a time. It seems my HDMI and extra VGA port in the back on my pc are not working for some reason, possibly because they aren't connected to anything inside as I found similarly with my Ethernet port. Is there anything I can do from home to resolve this issue or will I have to buy lots of external components in order to dual screen.

Yeah, there isn't anything attached to the inside of the ports, just opened it up, looks like a few things inside aren't actually connected by anything. Pretty annoying. Had a similar problem a year or two ago, my ethernet port wasn't connected inside so had to get a friend to add one. Would it be possible to add a HDMI port that was actually connected and therefore worked