I had an itune acct a couple of years ago. and had lots of music on it. I now downloaded itunes to my new lap top where is my music

Is this music that you purchased? If so, you can go to the Purchased tab of your iTunes account and download the old music. The music does not automatically appear in your account when you install iTunes on a new computer. Your library would not be on a new computer. If the music is content that you added to iTunes library from other sources, then that would be on the old computer you had iTunes on. There is no way to recover that, unless you have it on a device that you sync with iTunes.

You must be using the same Apple ID used to purchase the iTunes content, (couple of years ago).