Myos is windows vista,I downgrade it to windows xp3 sata,after that long instalation my wireless cannot detect network evev in range?I need your pecfect answer right now.thanks in advanced!

Only thing you can try is to go to the website for your laptop model and download the wireless drivers from there and install.

Since you've reformat your laptop, the only thing you can do is to install the driver of your laptop, specially the network driver.

I do NOT recommend downgrading a Vista machine to XP. Often the hardware in a Vista machine is Vista specific and will not work under XP.

My suggestion is to use the Recovery CD or partion and go back to Vista.