Purchased OSX Lion on macbook from App store, but when I go to download the gray download bar is unresponsive.

I have an old 2008/2009 macbook that recently I had to wipe due to an issue. I purchased snow leopard and got my OSX up to 10.6.6. Now I am ready to download Lion. I purchased this from apple and they sent me the code to download it from the App store. However, when I go the the app store under purchased it does not respond when I click on the download button. I have cleaned out a number of my large files so memory should not be the issue. The download bar is gray with white lettering. I tried talking to apple support but they told me my computer was so old that nobody knew how to work with them. Thanks in advance for any assistance.