Installing windows from a USB drive has a few advantages—a small USB drive is much more convenient for carrying around than a DVD,One can use a USB key to install Windows on systems that do not have a DVD drive, such as a netbook.

So,If you have a damaged CDROM drive or systems without DVD drive and want to install Windows on your computer or laptop, then I recommend that you use Novicorp WinToFlash, which allows you to boot Windows operating systems from a USB flash drive.

Follow the steps one by one:

• First of all download "Novicorp wintoflash" from the link given below,

http://wintoflash.com/download/en/

• Format your USB drive.
• Now, open "WinToFlash.exe" from downloaded folder.then,select Advanced mode tab.
• Determine the operating system that you are going to use, for example,If you want to install Windows XP, you have to select in Task option Transfer Windows XP/2003 setup to USB drive, then click Run button.
• Select now Windows source path (where i386 folder is located), then select your USB drive. Click now Run button.
• Select I Accepted the terms of the license agreement, then click Continue
• A small window will pop up which alerts you that all your USB flash drive data will be erased, click OK.
• Windows files will be trasferred to your USB flash drive.
• Click OK when the transfer process is finished.
• That's it. The USB flash drive is now ready for use to install your operating system. Restart your computer and enter BIOS setup to make your pc boot from USB drive.