Question : I have downloaded the zip of windows 7 for 30 days evaluation version. but now i'm trying to write it to a DVD to make it to boot windows 7 to install in my laptop. i copied the files using nero 8.

I have downloaded the zip of windows 7 for 30 days evaluation version. extracted it.now i'm trying to write it to a DVD to make it to boot windows 7 to install in my laptop. i copied the files to dvd using nero 8.
It is not booting from the new DVD which i copied using Nero 8. enabled the boot from cd option in the bios setting. How do i make it bootable ?

Answer : I have downloaded the zip of windows 7 for 30 days evaluation version. but now i'm trying to write it to a DVD to make it to boot windows 7 to install in my laptop. i copied the files using nero 8.

Yes, MS do evaluation Windows 7, but only Enterprise edition. You can download it here:
http://technet.microsoft.com/en-us/evalcenter/cc442495.aspx

And as jakethecatuk sad above it must have ISO extension, that can be sucessufly burn to DVD disk.
Also you can check checksum after downloading you Windows 7 copy.