It is very convenient to install MS Windows 7 from USB flash. If your CD/DVD drive damaged than you can gain benefit from it, or you if you in hurry to install OS. Follow the steps below to prepare a USB flash for USB booting. For this you need a MS Windows Vista or MS Windows 7 installed PC, MS Windows 7 DVD. 1. Take a 4 GB or larger flash drive and format it using FAT32 or NTFS file system. 2. Now run command prompt or DOS from Start> Accessories >Command prompt or just press Windows logo key+R, it will show a dialog box (Run) where you have to type "cmd". It will run command prompt. 3. Now in command prompt type DISKPART, 4. Type LIST DISK, it will show existing Hard Disks inside your PC like HDD 0, HDD 1, HDD 2 5. Type SELECT DISK 1 (Depending on flash drive number it may be 1, 2 or 3) 6. Now type SELECT PARTITION 1 7. Type ACTIVE 8. Type EXIT 2 times. Now copy all files from MS Windows DVD to your flash. It is ready. Now you can install MS Windows 7 from your flash drive. Plug the flash drive in a USB port in which PC you want to install MS Windows 7. Now power on your PC and press the special Function key (Boot Key F12, F9 OR Esc), and select the USB Storage, USB HDD as your boot device and press Enter on keyboard. It will start the installation of MS Windows 7.