Xbox 360 - Xbox original games question???

I've been trying to work out how to get my new 4gb slim 360 to play my original Xbox games.

The original Xbox games I have are on the backwards compatible list...so no problems there.

When I first tried to play the games there was an error message telling me I needed a hard drive....which I have since purchased and installed.

I now get an error message telling me I need to download the games again (?)....I had a Xbox Live gold trial membership which expired just prior to me installing the 250gb HDD....do I need to get a gold membership to be able to download the files/updates required?

Any help or thoughts would be greatly appreciated!!

not 100% sure mate

this forum might help if you cant get an answer here
Xbox.com

I think you need to download some update/compatible thing so the game will work. Not 100% sure though.

You need to go onto pay like $50 and then go onto Xbox Live and download something. I don't know, I have never and never will pay to play online.

Yeah you need to have your 360/slim online insert the game and it'll tell you that it needs to install something (might need to renew membership) and after the download/install you'll be able to play it, i did it with GTA san andreas