Sometimes we have to open up our PC's case to get inside to add memory, a new graphics card, or whatever. Unfortunately, as easy as this is, it also allows plenty of chances for static electricity to pass through to the components and damage, or even destroy them. static is a lot more common than you might think, and it's not just caused by carpets and doorknobs. It can happen when just about any two objects either separate or rub. Take these tips to avoid having to start all over again:

Have the same electrical potential. The simplest and easiest way to do this is to simply ground them. A while back that wouldn't have been very difficult at all, you could just touch your PC whilst it was off and still plugged in (because the ground would do the job for you). But no longer, as many more recent motherboards have low voltages running through them if they're plugged in at all. Therefore the opposite is true now - you must unplug a PC fully before working with it.

Also, use a wrist strap, and the more expensive the better. Some of the more cheap models are inneffective or even don't work at all. Remember to ground it!

Make sure that the area you want to work on is free of other static-inducing components - a wooden table with nothing on it would be great. Keep plastics, bins, and phones away from you, and whatever you do, don't sit down while doing it. A chair can be bad enough at generating static, but a rolling chair is a magnet for static potential.

Buy a grounded rest for your PC. I would reccommend using them, but they're only really worth it if you are planning on getting inside your case regularly.

Also, up the humidity, as a low humidity makes for a higher amount of static. A lot of modern vent systems allow you to adjust it - a humidity level of 45 is right about perfect for the job. Even if your ventilation system doesn't allow you to adjust it, you can do it on a cold day, because the humidity will be low, or just stick the AC way up high.

At the end of the day, even following all the advice above, you simply can't 100% guarantee that you won't get static discharge, but if you follow these guidelines at least it will be significantly reduced.