Clean install of Lion I have a 1st generation MacBook Air running Leopard 10.5.8. Recently it's not working very smoothly anymore. I've my Lion 10.7.4 retail DVD with me. When I boot up to the Lion CD, it shows that I can't update from the current OS. 

So if I use Disk Utility to format the hard drive, then will the installation install a new, clean Lion to my hard drive?
From the Apple OS X Lion website:


  General requirements: 
  Mac computer with an Intel Core 2 Duo, Core i3, Core i5, Core i7, or Xeon processor


The MacBook Air 1st gen has a Core 2 Duo processor. source

So it should work.