Close all programs, and then restart your computer.
Insert the Windows DVD into the computer's disk drive. Wait for Setup to start. If Setup doesn't start automatically, follow these steps:
Click Start, and then type Drive:setup.exe in the search box, where Drive is the letter of your computer's DVD drive (for example, D:setup.exe).
In the Programs list, click Setup.exe.
Click Install Now.
Click Go online to obtain the latest updates for installation (recommended).
If you're asked for it, type the Windows Product key.
In the Which kind of installation do you want? window, click Upgrade.
When the installation is complete, restart your computer, and then run Windows Update.