13. Filter out their fun in IE
In Internet Explorer, you can use the Content Advisor to block sites that your victims tend to visit regularly – Facebook, Ebay, or Google, for example.
To do this, go to 'Tools | Internet Options | Content' and then click 'Enable'. Now click 'Approved Sites', enter the domain names to block and hit 'Never' to add them to IE's blocklist.
14. Make the browser cache go crazy
For causing maximum chaos with minimal effort, switching the browser's cache directory to the desktop takes some beating. The result is a victim snowed under with copies of every web page and online image they view.
The setting you need lies in 'Tools | Internet Options | Browsing History | Settings'; click 'Move Folder', select the desktop and then press 'OK'.
15. Fiddle with the default home page and search
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Here's an easy one: switch your victim's homepage to a new and annoying location (or even for a collection of homepages) that will load each time the browser runs.
To do this, just alter the homepage specified in IE' s Options menu. Loud is good if you're aiming for maximum embarrassment: we like the mellifluous tones of www.zombo.com, but you may prefer something more akin to the website for the incomprehensible kids' programme Yo Gabba Gabba!
While you're at it, you can also change the default search provider to something such as the Daily Mail rather than Live Search or Google. To do so, visit this page, install the provider you want to use and make it the default in Internet Explorer's main Options screen ('Search | Settings').
16. Eliminate the address bar
It's easy to hide IE's various browser toolbars, but to get rid of the address bar as well – and effectively render Internet Explorer useless – you'll need to employ a quick registry hack. You can find the instructions you need for this at site, but remember to take a note of the original settings so you can undo your changes later.
17. Turn the web upside down
It's not for the faint hearted, but if you follow the instructions here, you can render every web page your victim views upside down, but leave the rest of their display options intact.
18. Make Google widiculous
Google's preferences include a few fun gems that can cause mirth and merriment. For example, you can change the Interface Language to 'Elmer Fudd' and see the internet suddenly develop an obsession with that wascally wabbit. Or try 'Bork, bork, bork!' to see the search giant presented in the words of the Swedish Chef.
19. Bring on the Blue Screen
The dreaded Blue Screen of Death error message can be summoned at any time with the marvellous BSOD screensaver from here. It looks just like the real thing, although it can be dismissed pretty easily.
20. Treat them like a toddler
If you've got admin access, Windows Vista's parental controls can be a hoot: not only can you block specific programs, but you can lock people out of the system altogether at specified times of the day. We'd strongly advise you not to turn on the logging features to find out what people use their computer for, though. The phrase 'too much information' definitely applies here.
21. Abuse accessibility
Windows Narrator ('Start | Run | Narrator') is great for people with visual problems, but it can also be used to annoy people. Turn it on and select 'Echo User's Keystrokes' (Vista) or 'Read Typed Characters' (XP) to have the Narrator babble on whenever your victim touches the keyboard. For added fun in Vista, click on 'Voice Settings' and turn the speed, volume and pitch settings to maximum.
22. False error messages
Visual Basic is a wonderful thing, especially when it's misused. To write your own suitably scary error message, open Notepad and create a file with the following: 'x = msgBox("Scary message goes in here",,"Window title goes in here")'.
Now save the file and give it the extension '.vbs'. To bring up the message, simply double-click the file you've just created. Remember to close Notepad, so you won't give the game away. Put stupid things in Startup Anything in the 'Programs | Startup' folder launches when Windows runs, so the possibilities for fun are endless.