Hi Alice,
Welcome to Microsoft Community where you can find the answers related to Windows.
The 1722 error message is a general installer error message that states that a system level failure has occurred. In most cases, you experience a setup failure in the Setup program that is associated with registering fonts.
It would be great if you can reply to these questions in order to assist you further.
1. What happens when you try to install Windows update?
2. Have you made any changes to the computer prior to this issue?
I would suggest you to check the Windows Installer Services status.
Step 1:
Check the Windows Installer Service.
a. Click Start, in the run box, type Services and press Enter.
b. Scroll down and find the Windows Installer. Double-click “Windows Installer” in the Services list.
c. On the General tab, make sure the service is started under “Service status”.
d. If the service is not already running, under Service status, click Start, and then click OK.
Step 2:
Unregister and re-register the Windows Installer
a. Click Start Orb, in the start search box, type MSIEXEC /UNREGISTER, and then click OK.
b. Click Start Orb, in the start search box, type MSIEXEC /REGSERVER, and then click OK. After you run this command, the operation is complete.
c. Now, restart the computer and check if it helps.
Reference:
Troubleshoot problems installing and uninstalling programs on Windows-based computers: http://support.microsoft.com/kb/2438651
Clean boot: Once you are done with the troubleshooting, perform the steps from Step 3: to reset computer as usual.
If you need any other information about Windows, feel free to post your questions and we will be glad to help.