Cut from your post, pasted to Word, cut from word, pasted here:

Until recently I have been able to highlight, cut and paste information from the Forum to Word or another word processor for my own archives.

(Italics added) No visible problem.

A most probably cause is that your Temp Space on your hard drive is so jammed full that there's not room for the clipboard. A hard drive that's just too full (too little free space), badly fragmented (too little usable free space), or too many things loading at Startup so that your RAM is overstuffed.

Assuming you're using Windows(?)

In IE, Tools|Internet Options, General Tab, Delete Button, will let you remove Temporary Internet Files that may be choking your system. You'll get a chance to choose what to delete after you click that first button, so don't be bashful. Check your other browser if needed to find a similar place.

Since files that are open can't be removed, a better, and more thorough method is to close all files:

Start|Programs|Accessories|System Tools|Disk Cleanup

Usually clearing up the trash will restore the clipboard (Copy/Paste) function. Occasionally a defrag may also be needed.

Recent Windows version can use a maximum of 10% of the free space on the hard drive (as normally set up), so if you have less than 20% free on your main hard drive, or in any case less than about a couple of GB of "emptiness" you might want to look at offloading some stuff to a backup.

Windows cannot (actually it's more will not) defrag a Hard Drive if the free space goes below 10% of the drive usable size, so a 160 GB drive (~150 GB useful) needs at least 15 GB (20 GB is better) to be "cleanupable."

John