Open Windows Internet Explorer. Have it declared as the default browser. But turn off the option to check this when the browser opens (If you want).

Now do the same thing using Firefox.

Thank you for getting back to me so quickly. The hiccup in your response is IE causes my entire computer to lock up, so I removed it from the Control Panel. Mozilla/Firefox start page is my home page.

So is everything okay now?

Note: Windows uses IE to perform its updates.

Perform a System File Check to fix corrupted system files Win 7, 8, 10, Vista: https://support.microsoft.com/en-us/kb/929833 Win XP: https://www.microsoft.com/resources/documentation/windows/xp/all/proddocs/en-us/system_file_checker.mspx?mfr=true