Since the Win10 technical preview version is still in the testing phase, there are still many problems like the following. Therefore, if you do not particularly need users, it is recommended to wait for the official version of Win10 to be released before upgrading. This can avoid many problems.

However, we have a more convenient way to install it, which does not require Internet downloading. It can be done using DISM (Deployment Image Services and Management) and the installation image of the Win10 Technology Preview version. Let’s take a look at the specific methods below.

1. Load the image of Win10 Technology Preview. In the Win10 preview version, you can load the ISO image file by double-clicking it, or you can use the soft media virtual optical drive in the Rubik's Cube to load it conveniently;

2. Right-click the Win10 start menu button and select "Command Prompt (Administrator)" to open the command prompt;

3. Directly enter the following line of command in the command prompt. Of course, you can directly paste and copy it. Remember? The Win10 command prompt can now directly use shortcut keys such as "Ctrl+C" and "Ctrl+V", and then press the Enter key. Note that "D:" is the drive letter name where the installation image is located. This needs to be modified according to the actual situation of your computer. Next you should see a progress bar, and when completed it will prompt "The operation completed successfully";

Dism /online /enable-feature /featurename:NetFX3 /All /Source:D:sourcessxs /LimitAccess

4. Go to "Turn Windows features on or off" in the control panel to see if .NET Framework 3.5 has been installed and enabled?