You have need :
1.Windows 7 Ultimate DVD bootable
2.A PC with : 1 Ghz or faster 32-bit (x86) or 64-bit (x64) processor
1 GB RAM (32-bit) or 2 GB RAM (64-bit)
16 GB available hard disk space (32-bit) or 20 GB (64-bit)
DirectX 9 graphics device with WDDM 1.0 or higher driver
Step 1: Place Windows 7 DVD in your dvd-rom drive and start your PC. Windows 7 will start to boot up and you will get the following progress bar.
Step 2: The next screen allows you to setup your language, time and currency format, keyboard or input method. Choose your required settings and click next to continue.
Step 3: The next screen allows you to install or repair Windows 7. Since we are doing a clean install we will click on "install now".
Step 4: Read the license terms and tick I accept license terms. Then click next to continue.
Step 5: You will now be presented with two options. Upgrade or Custom (Advanced). Since we are doing a clean install we will select Custom (Advanced).
Step 6: Choose where you would like to install Windows 7. If you have one hard drive you will get a similar option to the image below. You can click next to continue. If you have more that one drive or partition then you need to select the appropriate drive and click next. If you need to format or partition a drive then click Drive options (advance) before clicking next.
Step 7: Windows 7 starts the installation process and starts copying all the necessary files to your hard drive as shown on the image below
Step 8: It will go through various stages of the setup and will reboot your system few times.
Step 9: When your PC reboots it attempts to boot from DVD as its the first boot device. Do not press any key during the boot prompt so Windows 7 will continue with the installation by booting from the hard drive.
Step 10: After the reboot your computer will be prepared for first use.
Step 11: At this stage you need to choose a user name and computer name. Click next to continue. The user account you create here is the Administrator account which is the main account for your Windows 7 that has all the privileges.
Step 12: Choose your password and password hint just incase you forget your password and need to jog your memory
Step 13: You can now type the product key that came with Windows 7 and click next. If you do not enter the product key you can still proceed to the next stage. However Windows 7 will run in trial mode for 30 days. You must therefore activate Windows within 30 days otherwise you can not access your computer after 30 days.
Step 14: Help protect your computer and improve Windows automatically. Choose Use recommended settings
Step 15: Review your time and date settings. Select your time zone, correct the date and time and click next to continue.
Step 16: Select your computer's current location. If you are a home user then choose Home network otherwise select the appropriate option.
Step 17: After the final restart Windows 7 will start to boot up
Step18: Finally you have the logon screen. Just type your password and press enter or click on the arrow to logon to Windows 7 for the first time.
Step 19: After you have logged on to Windows 7 for the first time, you will see similar desktop to the image below. At this point you can start using your computer. However it may not be fully configured. You need to make sure that all the hardware is detected correctly and the necessary device drivers are installed. This can be done from the device manager.