OK, I was first thinking you were talking about a handheld, physical calculator. Then i got to the part about the red HTML text and I thought, is this a surreal situation [SS]. So I had to make the leap to: "Hmmm, perhaps he's talking about the Calculator provided on this site."
So, if you are willing, this can be a teachable moment for you -- especially if you make a habit of communicating this way. Do people often say, "What the heck are you talking about?" when you converse with them? Then the clue to why is contained, here. Think _establishing context_, and _supplying pertinent framework_ -- or if that doesn't make sense, then try putting yourself in other peoples shoes and ask the question,_ would I understand what the heck I'm are talking about_?
So, if I assumed correctly, try dumping the cache on your browser. Especially if you're using FireFox -- there's some sort of bug that causes sites to go haywire and dumping the cache is the workaround.
If my assumption is incorrect, then perhaps you've been hacked
