Really? I'd take a vested interest in his life too. Even anaracho47 must think violence is the answer now :D Anyway;Part A:Switch off your interwebz. Disable connection etc.You may need to clean your system of keyloggers, they come in two forms, hardware and software.He may not be using them however, he might just be using wireshark or some other backtrak utility to observe your packets.This is an easy fix, just get an Ethernet cable for your interweb. No wi-fi, no problem. This is the most likely scenario, since it's easiest.If he's actually installed a hardware keylogger, then you've more work to be doing. - check the cable on your keyboard   - open the keyboard itself and look at the back where you should see a little prefab circuit. If you see any weird attachment-like thing connected to the little PCB, that's bad. Rip it out.  - trace the cable back to the PC, do you see any adapter-like looking thing? Your cable should be just that, pure cable until it reaches the USB connection. Any plastic 'adapters' between the keyboard and USB are likely wireless key-loggers.That should take care of most hardware keyloggers unless he's working for the CIA or something.Now, a software keylogger involves a bit more effort, although it's usually easier to detect and remove. - Since this a tech engineer, I'd go for the nuclear option, remove binaries you want to keep to a external HD. Shut it off and then do a full wipe reinstall of windows (ideally linux, but you know...)Also;- If your router is using WEP, upgrade it to WPA 2.0 or 1.0 if you can. Otherwise get a new router. Make sure your router/wifi password is superdoubleplusgood. - Run antivirus on your external HD just in case.Part B: ~ The Non-Violent Passive Aggressive Approach- Get his cellphone number. Google SMS bombing, there are services on TOR that do this, so it's tiem for you to do some research. You're going to turn his phone into an expensive paperweight, it's so easy to do and so satisfying. - If you can get into his house, then put a hardware keylogger onto his keyboard's USB cable. You'll need a wireless version, it'll appear like a mobile phone to him, so it won't be too suspect. He'll probably find it eventually, but who the fuck cares once you've pillaged his facebook, email, porn and linked-in accounts such that he'll become a social outcast.- If that seems too adventurous, use a prepaid phone to order COD pizza to his house. From every place in the city. A geek who doesn't have pizza on demand is likely to eventually suffer nervous breakdown. - If he has a girlfriend/wife, send a salacious letter from an unknown admirer with red lipstick marks on the envelope seal and a kiss imprint on the paper. 99/100 the woman will open it and your dear old pal, after he's done explaining himself, will be walking like cat on hot bricks for the next couple of months. Ought to keep him busy.I'm running out of ideas, halp you guys!