Attach Windows installation media to provide required files by following these instructions:

Find and attach the EBS volume

1. Find the snapshot ID for the Windows installation media that corresponds to the Region your EC2 instance is in at Configuring Windows Components on Amazon EC2
   .
2. Open the Amazon EC2 console and choose Snapshots.
3. Open the drop-down menu under Create Snapshot (next to the search window), and then choose Public Snapshots.
4. Locate the Windows installation media snapshot by using the query Snapshot ID : snapshotid, where snapshotid
   matches the Windows Installation Media snapshot ID for your Region.
   
5. Select the snapshot, open the Actions menu, and then choose Create volume.
   Note: When you create the volume, be sure to select the Availability Zone that corresponds to the Availability Zone for your EC2 instance.
6. In the Create Volume
   dialog box, choose the Create button.
7. From the left navigation bar, choose Volumes.
8. Select the new volume, open the Actions menu, choose Attach Volume, enter your EC2 Windows instance ID, and then choose Attach.

Bring the volume online

1. Connect to your instance using the Remote Desktop Protocol (RDP), as described at Connecting to Your Windows Instance Using RDP. Be sure to log on with an account that is a member of the local Administrators group for the EC2 Windows instance.
2. Right-click the Start button and choose Disk Management.
3. From the list of volumes displayed in Disk Management, choose the new volume.
4. Right-click the disk that corresponds to the new volume.
5. Choose the Online option.

After you bring the disk online, install the .NET Framework on your EC2 Windows instance with the Add Roles and Features Wizard or by using PowerShell as described below:

To install the .NET Framework using the Add Roles and Features Wizard

1. In Server Manager, choose Manage, and then select Add Roles and Features to start the Add Roles and Features Wizard.
2. On the Select installation type screen, choose Role-based or feature-based installation.
3. Select the target server.
4. On the Select features screen, check the box next to .Net Framework 3.5 Features.
5. On the Confirm installation selections screen, a warning appears: "Do you need to specify an alternate source path?" If the target computer doesn't have access to Windows Update, use the Specify an alternate source path link to specify the path to the \\sources\\sxs folder on the installation media and then choose OK. After you specify the alternate source, or if the target computer has access to Windows Update, click the X next to the warning, and then choose Install.

If you are using Server Manager in Windows Server 2012 to add a role or feature to a remote server, the remote server’s computer account (DOMAIN\\ComputerName$) requires access to the alternate source file path because the deployment operation runs in the SYSTEM context on the target server.

Finally, confirm that you successfully installed the .NET Framework 3.5 by following the steps in How to: Determine Which .NET Framework Versions Are Installed.