Thanks Shorena,
I presume you just mean when I click on it, it should open up in my Firefox or Chrome browser, but it doesn't. It just comes up 'windows can't open this file & then click here to find a programme which will, but still nothing happens, either online or offline. I'm gonna try tomorrow on a friend's computer as I'm getting nowhere with this one.
The .html File should open yes, if you doubleclick it. The .sig will not, unless you have a programm linked to it, which usually isnt the case with windows and linking notepad to it makes no sense.
If the .html file is not opening you usually can open your favorite browser first and just drag the file into the open browser window in order to open it locally.