Replacing parts on a computer is not very difficult to do. I replace parts on my computers at home, but when it comes to buying a new one, I let the computer store assemble it for me.
When friends and/or family ask me to build them a computer, I give them a list of parts and tell them to fax and/or bring the list to several computer stores for a quote.
The reason is because it is better to get someone experienced to do it. If a part is defective and/or does not work, the shop will replace the part.
Therefore, I always recommend getting the computer shop to install the parts.
A knowledgeable friend can be called to install a specific part that needs to be replaced. For example, I have installed a power supply, video card, and hard drive into a computer.
But when it comes to automobiles, doing the repair yourself is not a good idea. Technology is making repairs difficult for non-dealerships. Therefore, if you automobile needs repairs done, bring it to a shop. With technology built into many automobiles, a simple repair may require a technician to reset the onboard computer.
Do-it-yourself car repairs no longer a viable option
Dealerships fight for right to fix automobiles