What is the best way to prepare a computer for installation?
I always start any installation by using a memory test utility to completely scan the new RAM to check that it does not have bad areas. This is also good to check that your chosen memory speeds do not result in data corruption. It is possible to choose too high a speed which results in data corruption. So you really want to set your memory speeds before you start installing especially if you are going to overclock the memory. If your speeds do not past the memory test then when you start installing windows you will have "could not copy file" errors and that is just the start of the problems you will have. So check it first.
Also try to buy good quality ram. I like Kingston ram because it has good availability here and comes in a package which avoids damage. I have also had no problems with Samsung, TwinMOS, JetRam, Siemens, Hynix but I have had problems with Elixir and also one problem with Micron Technologies chips in an OEM package. It is better to avoid OEM chips and buy ones that come with a lifetime warranty. The problem is that a poorly manufactured stick of ram can have a failure after several years which will cause data corruption. Maybe your supplier will not replace the ram after several years. Some OEM chips do not even show the company that assembled the stick so who will you complain to then?. The manufacturer of the actual chips and not the stick probably will not agree to replace the stick and will direct you to contact the OEM manufacturer.
I also like to buy Western Digital hard disks (Seagate is good also but I do not buy them because their test utility is so slow) and I use the manufacturer's WDDiag utility to scan the hard disk fully before starting any installation. I have bought one or two hard disks which had errors so instead of sustaining future data loss problems, I take them back to the shop immediately if the test does not report "no errors". You also want to read the motherboard manual and check that all jumpers and bios settings are as you want them. Once you have done all this you will have built a solid foundation for your installation. You will most probably have an installation without issues and build an excellent PC.
I am choosing a new system and I do not want to have capacitor failure issues, what should I look for in a new board or a second hand board?
It is indeed a good idea to check the manufacturer of the capacitors on your new or second hand board of choice. You want to see Japanese manufacturers like Rubycon, Nichicon, Sanyo, Panasonic.Especially if you are buying an old board with a chipset from BX type to today's offerings. Due to problems with an incomplete electrolyte formula stolen from Rubycon and used to produce electrolyte for low ESR capacitors by Taiwanese manufacturers, the capacitors produced would fail from 1 year of using the board rendering the board useless unless repaired. I have had several boards fail like this so watch out. Intel generally uses very nice components on their boards but you give up the right to overclock.
Watch out for RULYCON caps which are counterfeit versions of the premium Japanese RUBYCON caps. Don't expect the same performance at all.
How should I look after my system
The most important part of looking after your new computer is to listen to it. Get used to the sound it makes and remember those sounds. Check where the sounds are coming from in order to distinguish which component makes each sound (Power Supply Fan, Processor Fan, Case Fans, Hard Disks, Optical Drives). Then when the sound becomes different you can determine which component is developing a fault.
This is especially important with hard disks because abnormal clicking or high frequency sounds can indicate a hard disk that is going to fail shortly. Take action before you lose your data. If a hard disk develops very slow response, this is another indication of a problem. However hard disks from different manufacturers also make different sounds. Some make rather worrying sounds in the beginning. So get used to the sounds they make when new.
Here's hoping that you find a useful solution here.