A few weeks ago, my car wouldn't start. As it had the original Lexus battery, I took it in and was told I needed a new battery (no surprise), which I purchased and installed. This morning, I had to move my electric seat up. As I was pushing the seat button, I thought I would multi task & go ahead and start the car while the seat was moving up, so I put my foot on the brake and pushed the start button. Immediately, the seat stopped moving and the car didn't start- not a sound, click, etc, none of the warning lights came up-totally dead car. Any ideas what to do?

 

[EDITED - I see you mention the seat was moving at one point, so the below doesn't apply]

Sorry, but I have to ask ... did you get the polarity correct?
I once attempted to install an almost new battery I had on-hand to my Lexus which fit dimension-wise in the battery tray. However, I then realized the polarity was opposite of the battery cables when I went to connect it.