Q: I am trying to watch movies from my iMac on my Panasonic TV

Depending on your year and model iMac, you will need a Thunderbolt to HDMI adapter or Mini Display Port to HDMI adapter.

http://store.apple.com/us/product/HA824ZM/A/belkin-mini-displayport-to-hdmi-adap ter?fnode=51

or

http://www.amazon.com/EnjoyGadgets-Thunderbolt-video-adapter-support/dp/B006GH8V I4

You need a MiniDisplay Port to HDMI adapter or cable.

Good Luck

I'll add some additonal advice and help.

If you want to speed up your current iMac, your model can take a total of 8 GBs of RAM memory.

Here are the specs. for the RAM modules you need.

You can purchase correct and reliable Mac RAM from online Mac RAM sources Crucial Memory or OWC (macsales.com).

Here is what you need from OWC.

http://eshop.macsales.com/item/Other%20World%20Computing/8566DDR3S8GP/

and how to remove and install new RAM here

http://eshop.macsales.com/installvideos/imac_mid_2007/

Good Luck!

Not sure, but check out this discussion and this link.

https://discussions.apple.com/thread/4989455?tstart=0

and this.

http://support.apple.com/kb/HT4241