No big deal about Cab files - they're just copies of the operating system files. Not like registry files, for instance.
My guess is that all this advice (since, and apart from, Max's) is way over the top, and all will be well for Kendall, once the programme (in this case the browser) has been cloesd and restarted.
But where memory is getting used up in an unusual way, as in Bill D's post, or Windows itself is slowing down, or anything odd starts happening to the desktop, it is good housekeeping to suspect a viral infection. There are one or two around which are very prevalent, but fortunately not too destructive, that can get into some versions of Internet Explorer without you needing even to open the file that brings it in. This known weakness can be plugged by downloading a free file from Microsoft.
For more on this, try separate Google searches for "wscript" and "help.vbs".