If you can't solve Failed Code 1638 issue by yourself, you have the following options to fix Failed Code 1638 problem.
1.Press Win + R, type service.msc in the search box, clicking OK.
2.On the Service window, find the service you want to uninstall, for example Application Experience, double-click on it and copy its service name - AeLookupSvc.
3.Press Win + R, type cmd in the input box, press enter.
4.Type sc delete AeLookupSvc, press enter.
5.Press F5 to refresh to service window, you will find AeLookupSvc is disappeared now.
First, open up Notepad by pressing Windows Key + R to open Run and type notepad to get a new Notepad window. Paste the following text:
Windows Registry Editor Version 5.00
Save the file with CTRL + S --- name it whatever you like, but be sure that it ends in.reg to make it a Registry file.
Double-click the new file and confirm adding it to the Registry.
Now, you can restart the computer to re-enable automatic updates, or open the Start Menu and choose Control Panel > Windows Update to check for updates on the web manually. You should find new updates waiting for you, despite XP not receiving any updates since 2014.