i have lots of downloaded avi files that i want to put onto a usb stick to play on my tv. if i simply put it on the stick the tv tells me its an unsupported file. what file do i need to convert them too to play on my tv and what software should i use?
There are many problems here. First of all you need to find out which file types and which audio and video codecs that your TV supports playing back from a USB stick. To determine this you need to either have some reference files (to inspect) that works on your TV or look through the manual/documentation from the manufacturer of your TV.
To find out which codecs are required by a given AVI file, you need to inspect the file with a multiemedia file inspector such as GSpot or AVIcodec.
When you have determined which format that you need to convert your files into, you can look here for programs that will help you accomplish this.