Download the ISO of your Windows 7 version from the links provided below:

Windows 7 Home Premium 32 Bit Windows 7 Home Premium 64 Bit Windows 7 Professional 32 Bit Windows 7 Professional 64 Bit Windows 7 Ultimate 32 Bit Windows 7 Ultimate 64 Bit

To activate Microsoft Windows 7:

Using an internet connection:

1. Select the Start button Start button icon, right-click Computer, select Properties, and then select Activate Windows now.
2. If Windows detects an internet connection, select Activate Windows online now. Administrator permission required You might be asked for an admin password or to confirm your choice.
3. Enter your Windows 7 product key when prompted, select Next, and then follow the instructions.

By phone:

1. Select the Start button Start button icon, right-click Computer, select Properties, and then select Activate Windows now.
2. Choose Show me other ways to activate.
3. Enter your Windows 7 product key, and then select Next.
4. Select Use the automated phone system. Administrator permission required You may be asked for an admin password or to confirm your choice.
5. Select your location (or the location nearest to you) from the drop-down list, and then select Next.
6. Call one of the available phone numbers listed. An automated system will guide you through the activation process.