QUOTE(carpetzone @ Jul 17 2007, 09:05 AM)

I bought Ad-Aware SE plus editon, three months ago. Do I have to buy Ad-Aware 2007 to improve protection in my computer?

No, Pro has some extra features for advanced users but the protection is basically the same. However, you can upgrade your Ad-Aware Plus SE to Ad-Aware Plus 2007 for free via the Support Center here:
http://www.lavasoft.com/support/supportcenter/