First go to internet explorer
and there there is a button called make default.
If that doesn't solve it try this.
1. Click Start, click Run, type Regedit in the Open box, and then click OK.
2. Locate the following subkey: HKEY_CURRENT_USER\Software\Classes\.html
3. On the File menu, click Export.
4. In the Export Registry File dialog box, enter HKCU_Classes_HTML_Backup.reg and click Save.
Note: This will create a backup of this registry key in the My Documents folder by default.
5. Right click the (Default) value for the .html key and select Modify...
6. Change the value from "ChromeHTML" to "htmlfile"
Repeat steps 1-6 for .htm and .shtml keys if they exist, remember to change the name of your backup file for each export