Popping the lid of a PC for the first time can be pretty intimidating, but there's really no need for concern. There's nothing inside that will hurt you, other than sharp edges and those devilish solder points. There's also nothing inside that you're likely to damage, assuming you take the few simple precautions detailed in this chapter.
Some PCs particularly those from office supply and electronics superstores have seals that warn you the warranty is void if they're broken. This isn't so much to protect them against your ham-handedness as it is to ensure that you have to come back to them and pay their price for upgrades. We advise friends and clients to break such seals if they need to, do their own upgrades, and fight it out later if they have a problem that should be covered under warranty.
We've never heard of anyone being refused warranty service because of a broken seal, but there's always a first time. If you have a sealed PC that is still under warranty, the decision is yours. Note that hard disks are a special case. Breaking the seal on a hard disk does actually destroy it and will without question void the warranty.
Those issues aside, feel free to open your PC and tinker with it as you see fit. Far from forbidding you from working on your own PC, most mail-order and retail computer vendors actually expect you to do your own upgrades. As a matter of fact, most of them will try to talk you into doing your own warranty repairs so that they can avoid sending a technician to do them for you. The rest of this chapter explains the fundamentals you need to understand to start upgrading and repairing your PC.