Internet Browsers Problem - Bold = Italics + Bold

I'm hoping that the title of this topic is pretty self-explanatory. For some reason this PC, a friend's that I am having to use since I moved in with them, displays all Bold text as Italics when you're using an internet browser (I've tested it both with Internet Explorer and AOL Browser). I've ignored this problem as long as I can out of politeness and not wanting to tamper witht heir PC, but it's really starting to annoy me, and my friend has given me the go ahead to do what I can about it. Within the Windows Start Menu, as well as MS Word, Bold and Italicised text displays as it should. Also, within internet browsers, italicised text displays properly. The problem is just with the Bold text, within an Internet Browser. If you'd like a screenshot then I can give one, but I'll wait to see if it's needed. Thank you to anybody who can help me resolve this issue.