Sir I'm A+ certified computer tech.
This is for internet explorer
What you have is a corrupt or damaged registry key in internet explorer Th registry key found at HKEY_Local_Machine\Software\Classes\htmlfile\shell\open\command
I'll bet you want to know how to fix it right lol.
For Internet explorer
Reset Internet Explorer.
To use the Reset Internet Explorer Settings feature from Control Panel, follow these steps:
1.Exit all programs, including Internet Explorer (if it is running).
2.If you use Windows XP, click Start, and then click Run. Type the following command in the Open box, and then press ENTER:
inetcpl.cpl
If you use Windows Vista, click StartCollapse this imageExpand this image. Type the following command in the Start Search box, and then press ENTER:
inetcpl.cpl
The Internet Options dialog box appears.
3.Click the Advanced tab.
4.Under Reset Internet Explorer settings, click Reset. Then click Reset again.
Click to select the Delete personal settings check box if you would also like to remove browsing history, search providers, Accelerators, home pages, Tracking Protection, and ActiveX Filtering data.
5. When Internet Explorer finishes resetting the settings, click Close in the Reset Internet Explorer Settings dialog box.
6. Start Internet Explorer again.
But I want to know which web browser are you using and which version of windows you are using as well.