I have set up a webpage www.time-to-unwind.co.uk and when I view it in Firefox, all the text has strikethrough - in IE all is OK. I had this issues a couple of years ago and fixed it, but could not remember how - it was to do with borders or cells I think. I am running Dreamweaver 6.1 in Windows 7 Ultimate.
Get the Firebug extension for Firefox
It'll show you that the cause is the line-through property in the text-decoration attribute on the <body> tag in
font-family: Geneva, Arial, Helvetica, sans-serif;
text-decoration: underline line-through;