This post is also known as "Your computer could be a chemistry experiment waiting to happen".
In my previous post on how to buy a computer, I briefly covered what to do when you receive a new computer but focused much more heavily on the topic of how to actually go about buying a computer. In this post, I will cover what to do before you use the computer for the first time to make sure what was built and sent to you is actually a quality product. You spent good money, let's make sure that no one cut corners where they shouldn't have and that all the parts are indeed correct.
This first part requires you to be static free. First, pull the computer out of the box. Now go touch a doorknob while grounded. Now, read the computer manual for opening up the box and follow the directions. Usually thumbscrews or screwless entry is used these days making it easy to open it up. Yes, it is scary, but opening the box won't void the warranty or service contract. The computer won't bite. Promise. Besides, in many areas of the world, the computer will likely have been sitting in an extreme temperature. Opening the box up will allow it to reach room temperature much more quickly.
Once the box is opened, check for condensation. If you see condensation, don't plug the computer into the wall for several days. Water and electronics don't mix.
The first thing to do is to take out one of the sticks of RAM and look at the pins. Gold should only touch gold connectors. Tin should only touch tin connectors. If the manufacturer mixed the two metals, you will get very slow corrosion that eventually introduces data errors, application crashes, and eventually blue screens. Like metals should only touch like metals. I picked this odd tidbit of information many years ago when I was building a system and the motherboard specifications said "gold pins" for the RAM. I did some Google searching and apparently manufacturers don't pay attention to this. If your manufacturer mixed metals, they are obligated to provide replacement RAM. Return the RAM to its cradle.
Next, go over and make sure all connectors are firmly in place. This includes all expansion cards.
Look at the direction of the CPU fan and where the graphics card is (if any). If the CPU fan is going to be blowing air onto the graphics card, then the computer is poorly built and will likely cause the video card to lock up. Send the computer back to the manufacturer or look for an alternate way to keep the system cool (e.g. liquid CPU cooler).
Check to make sure all hard drives are well-ventilated. Hard drives that get too hot have a reduced lifespan.
Make sure cables are out of the way of the main cooling system.
Check the CPU for anything suspicious. By this, I mean a loose heatsink, nearby wires that could melt, etc. CPUs and GPUs run hot. Most are in factory-sealed containers, but if they are open, it should be easy enough to tell. Most major manufacturers are usually pretty good about case design.
Make sure the motherboard is properly seated. This is harder to tell, but it should be firmly in place. If not, and you feel brave enough, take a screwdriver and tighten down the screws.
Search the Internet for each card and component on a separate computer. Make sure they are without fault. Be sure to check forums to see what people are saying about each item. Most items are OEM instead of retail. Cheaper, but sometimes lower quality with a higher fault rate. If possible, also try to determine the brand and model of the motherboard. Download the motherboard specifications from the manufacturer's website and make sure images match up. Figure out who exactly manufactured your video card (remember the GPU and the card itself are manufactured separately) so you can head off any trouble in advance.
Also, keep in mind that there is such a thing as "pirated hardware". Only a trained eye can spot the difference but if you experience problems with a particular component and replace it and the official component works as expected, perhaps you were using pirated hardware (even lower quality and very hard to detect).
Close up the box. Follow the directions to set up the computer.
Now reinstall the OS. If the manufacturer did not send you an OS reinstall disk, call them up and tell them to send one. Manufacturers are obligated to provide you one backup disk if you ask for it. If you have never installed an OS before, it is somewhat scary. Microsoft Windows is actually wizard/GUI-based and fairly automated once you get past the scary text-based interface. Reinstalling the OS removes all the junk the manufacturer installed that would significantly slow down a perfectly fine PC. Reinstalling the OS is usually fairly simple - turn on the computer, put the CD/DVD in the DVD drive, turn off the computer (hold the button for 5 seconds - don't worry, this won't hurt anything since you're going to wipe the drive anyway - it just forcefully turns off the computer), and then turn on the computer again. You may need to reboot again and press F2 or F12 or something similar to enter the system BIOS to change the boot order so that the CD/DVD drive is looked at first in the boot process instead of the hard drive.
After reinstalling the OS, you will note that it likely looks "ugly". Now you need to reinstall missing drivers. Typical drivers include audio, video, and display drivers and any drivers for third-party components (e.g. a digital camera, printer). I recommend installing the video driver first, the display driver if the monitor(s) is not recognized, and then the audio driver. If you have dedicated video and audio cards, go the respective manufacturer websites and download just the drivers for those devices (e.g. ATI has a big ol' GUI interface download and a drivers-only download - you really only need the drivers). I've found that after installing updated video drivers, it takes a couple reboots to "fix". Repeat the procedure for any third-party components you wish to use.
Depending on the OS and patches installed (e.g. Service Packs), you may need to install the latest updates for the OS before you install a specific driver. Pay close attention to what is the minimal needed.
Once you are done installing drivers, go to the OS update site and install all updates for the OS. This may require repeating several times and several reboots until all updates are installed. You should be connected through a router to the Internet. A Windows-based computer (especially an unpatched computer) not behind a hardware firewall will be compromised in under a minute on the big-bad Internet. The only way to clean a compromised system is to reinstall the OS. You have been warned! Get a good consumer router and put it between your computer and your cable/DSL line.
Once you have reinstalled the OS, the drivers, and it has been fully patched, reboot one last time. Now, install all the applications you want to use.
Once all the applications have been installed, check for updates to the OS and then each application. Repeat until the entire system is fully updated and set up.
Reboot one last time. Now you are ready to use the computer.
That is a painful process, but one you won't need to repeat for many years to come. This should produce a quality experience even for the cheapest of computer systems.
Every once in a while (once a year), you should open up your computer and take some compressed air for computers and, with the computer turned off, blow out most of the dust buildup. Also, look for the button battery on the motherboard and make sure it isn't corroding (don't remove it to check! It keeps the system time alive!). Remove a RAM chip to make sure the pins aren't corroding and then put it back into the slot. Make sure nothing looks "burnt". Close the box. You should backup the data on your hard drive (burn it to DVD or copy it to an external USB hard drive or use a secure online storage service or...LOTS of options). After backing up your data, do a defrag.