Change the start menu search so instead of finding local applications and files, it searches the internet.
Would be even funnier if it used the worst search engine available.
Oh wait…

I had a friend who sent me a “Y2K fix” program back in '99. Said it would patch the error so I’d be safe. When I ran it, it swapped the letters Y and K on my keyboard.

The version I recall was once if those Flash animations with a cute squirrel or whatever saying something… but it was really quiet so you’d need to turn up the volume to hear. Then partway through it changed to sex stuff and blasted out in a voice like a monster truck announcer

“anal sex dot com, all anal, all the time!”

I shall write a virus that makes the computer play the “USB device detached” sound followed shortly by the “USB device attached” sound. Dee doo. Doo dee. Just that. three or four times a week.

Alt+Tab goes to a random window instead of being in the order of recency

At first it all seems normal, every now and then a random sound effect is replaced by ominous hooting. Every hour, on the hour, a green owl flashes on the screen for a frame or two, it’s eyes boring into you before vanishing. Once every 50 or so times it pumps your volume up, selects speakers as output and let’s loose a screeching hoot. Random popups slowly ramping up “Restart your streak today”, “Where did you go?”, “Duo misses you”. At first just once or twice a day, but steadily increasing in intensity till it’s one every 23 seconds.

A virus that changes the font every time you go to a new page or hit refresh

I’ll call it Windows 11.

On my dads computer, back in the day, I set the sound for every action in Windows to a silly song i downloaded off kazaa (Windows xp days, i believe)

So this was the sound that played for clicking the start menu, hovering over programs/apps, whatever it was and making that menu appear, and any sub menu for individual games or apps following that. Any kind of prompt like errors or “are you sures” etc, minimising/maximising a window. Everything!

That’s what my virus would do. I just need the perfect sound to apply. Maybe that annoying tiktok song “Oh no! Oh no! Oh no no no no no!”

Occasional mouse and keyboard lag up to 1 second.

It was not a virus, but still great fun: coworker had a fat UNIX workstation, but no idea of the particulars except for the program he was using. I knew my ways around such machines, and I could log in from another machine via serial terminal.

What the coworker knew about the audio capabilities of his machine was the occasional “beep” it made. I found the “auplay” command, and a list of 8-bit audio samples.

So one day I was sitting at the PC next to him, logged in, and command ready to run, and waited for an error message to pop up. Then I pressed return, starting “auplay laughter.au”.

That face.

There’s a 1 in 50 chance that any copy text command cuts the text instead, and vice-versa.

Finds anything and everything that can be set to dark mode and sets it back to light mode, but not while you’re using it and not immediately.

When you click the mouse button, the pointer position moves up to 10px in a random direction before applying the click.

How harmless are we talking? I’m thinking of one that randomly “locks” the next file you try to open that was last accessed over 30 days ago. It prompts you with “File locked by last user, please enter username/email and password”

No matter what you enter, it unlocks the file.

Then the next time it triggers, it prompts you again, but blocks you from using the same username and password.

Rinse and repeat while the user keeps giving you all their user names and passwords over time.