Troubleshooting Windows activation problem

Please review the followings,

1. Verify the date, time and time zone of the PC is correct. Activation will fail otherwise.
2. Make sure the Windows system is installed with media from ITSC. Boxed products or Windows comes with a PC won't work with ITSC provided activation mechanisms.

For system using MAK activation, please perform the checkups below,

1. Check if the PC can connect to Internet, for example, by browsing to www.microsoft.com.
2. Make sure the correct activation key is used. For example, Windows 8 and Windows 8.1 have different activation keys.
3. Try activation at different times. MAK activation requires connection to Microsoft activation servers. Occasionally, the path to the servers may be interrupted.
4. For office PC, consider using KMS activation. KMS activation uses ITSC activation server which we have better control on the process.
5. Check if the latest activation code is used. Activation error 0xC004C020 implies activation quota exceeded and probably an old activation code is used.

For system using KMS activation, please perform the checkups below,

1. Check if the PC is connecting to the Campus Network. KMS activation doesn't work outside the Campus Network.
2. If the PC is using static IP address and not joined to the HKUST domain, add "ust.hk" to the DNS search suffix list.

Additional Resources

1. Get Help with activation error