3. The keyboard is the next suspect, since it shares the same (logical) serial port commonly used for the mouse.

A sticky or intermittent key can cause all sorts of erratic behaviour. Rather than "blowing it out," which - like my neighbor's leaf blower - just moves the crud somewhere else, I'd recommend a mini-vac. You can get an attachement set of nozzles that slip over the hose of any vacuum cleaner you have handy. Computer shops should have them, but the most reliable sources are places that sell "shop vacuums" like Home Depot etc. ~$10 US(?) and you never run out of air.

Especially with WinXP and recent office versions, there are an immense number of ways you can program your keyboard to act in abnormal ways. Most of these things are helpful when needed, but accidentally turning something on can produce lots of frustration. "Sticky Keys" and "Serial Keys" and "Filter Keys" are three functions that are "amusing," flipped on at a co-worker's desk (if you're into really juvenile behaviour).

At START | HELP AND SUPPORT, click the INDEX icon at the top and type "keyboard" in the search box. A little down on the list, at "keyboard combinations, " click on "walkthrough: personalizing your computer" and click the "Display" button at the bottom. This will open the "setup" routine where you can look at/for and "fancy stuff" that may have gotten turned on by accident.

As illustration of how complex this can be, my (came with the computer) keyboard is the "Microsoft Office" version that has individual buttons to turn on any office program, launch browser to normal home, hookup to the Office website, popup a calculator or calendar, etc. It also has a Back and Fwd buttons and scroll wheel built into the keyboard. I've covered most of them with duct tape.

John