Hi, welcome to the forums
1. Do you get any error message or error code?
2. Is it a 32 bit or a 64 bit computer?
3. Are you installing it manually or from Windows Update?
Make sure you have selected the right edition (32 bit or 64 bit) before downloading from the website.
Place the computer in a clean boot mode and install the update manually to check for the issue.
Steps to put the computer in Clean Boot:
1. Log on to the computer by using an account that has administrator rights.
2. Click Start, type msconfig.exe in the Start Search box, and then press ENTER to start the System Configuration Utility.
If you are prompted for an administrator password or for confirmation, type your password, or click Continue.
3. On the General tab, click Selective Startup, and then click to clear the Load startup items check box. (The Use Original Boot.ini check box is unavailable.)
4. On the Services tab, click to select the Hide all Microsoft services check box, and then click Disable all.
5. Click OK, and then click Restart.
Windows Virtual PC Download details: Windows Virtual PC