The answer to that question depends a lot upon circumstances: -

• 1) Has your existing computer broken down?
• 2) Are you simply fed up with poor performance?
• 3) Have you just been given a computer and decided that you’d like to rebuild it?
• 4) Are you just an ultra-geek who likes to stay at the cutting edge?

Section 1: Your existing computer has broken down/ gone tits-up.

If your existing computer has broken down, do you know exactly what is wrong with it?

• 1.1) Hard-drive or other drive.

• 1.2) PSU.

• 1.3) Motherboard. (Including chipset, audio codec, internal onboard NIC, etc…)

• 1.4) Graphics card.

• 1.5) Processor.

1.1) If it’s just the hard-drive or another drive that’s gone tits-up, then replace that drive.

There really is no need for a total rebuild unless you really want to do so: SATA and PATA drives are both still available new from suppliers at time of writing. Even if PATA drives have been phased out when you read this, it’ll probably still be possible to buy one secondhand from eBay or Craigslist. (See this article for more about SATA and PATA.)

1.2) If it’s the PSU at fault then a rebuild/new PC may or may not be necessary, depending upon the age of the motherboard. As a general rule I’d say that if the motherboard is 5 years old or more then rebuild or replace the entire machine. If you replace the machine it may be worth buying a secondhand PSU of comparable age, replacing the PSU, and using the machine as a second computer or server until it finally gives up the ghost.

Even if the motherboard is less than 5 years old at time of writing (March 2009) there may be issues with replacing the old PSU with a newer model. If the motherboard is 4 years old or more then I’d suggest doing as above and buying a secondhand PSU of comparable age and model. The reason for this is that, on older motherboards, the main supply wattage was delivered through the 5 volt rails, whereas with newer motherboards the power is mainly delivered via the 12-volt supply-rails. Also most newer motherboards have a 24-pin power connector to the motherboard and a 4-pin low-voltage connector exclusively to power the CPU. Older power supply units may not have provision for a 4-pin low-voltage connection, and also might only have a 20-pin power connector.

Whilst there are some brand new power supplies that have a 20-pin connector and an additional 4-pins available from another plug as an accessory to the main motherboard power connector – therefore the extra 4-pins can be left unconnected, as can the 4-pin CPU supply in the absence of a relevant socket for it on the motherboard; running such a setup will probably result in the motherboard demanding full-load or more from the 5-volt rails while drawing very little from the 12-volt supply.

This would be contrary to the purpose for which the new power-supply has been built; i.e. to supply the greater wattage via the 12-volt lines and deliver only a subsidiary supply via the 5-volt lines. The result being that the motherboard can’t draw enough wattage from the 5-volt supply and therefore fails in some way to deliver even the performance that you’re used to from the machine. This may even result in a frequent BSOD.

Ensure that the power supply you replace your old one with is up to the job as mentioned above… And don’t use a cheapo power-supply either: See here.

1.3) If there’s a fault on your motherboard then, if your PC is 3 years old or more, a total rebuild or a new computer would be the best option for reasons stated above, as well as to replace other ageing hardware before it goes to the great recycling plant in the sky. If your motherboard is less than 3 years old then it might be worth replacing the motherboard only; possibly upgrading it – and the processor to a better model.

1.4) If the graphics card fails then you’ll probably just be able to replace it with a better and newer card. If it damaged the motherboard by its fault, or if it’s onboard graphics running from the chipset on the motherboard, then section 1.3 applies.

1.5) If the processor dies, then there may or may not be a fault on the motherboard which has caused it to do so: Processors generally outlast motherboards in my experience*, so I’d probably be looking at section 1.3 in this case.

(*Here I’ll tell you of a case with one of my computers recently: A BSOD caused the computer to die. When I tried to boot up again the BIOS indicated that it was unable to find the processor. I didn’t rush to the conclusion that the processor had died, however. Further investigation revealed that the chipset on the motherboard had died; and as a result the BIOS was unable to access the processor via the chipset as it usually did. I don’t know whether the processor was damaged or not. I still have it but have never tested it. It’ll probably end up in recycling as I have no real use for a possibly faulty 32-bit single-core Sempron these days.)

Section 2: You’re fed up with the poor performance of your existing computer.

In that case yes; buy a new one, or if you particularly like the case, do a total rebuild. Sometimes it’s just not worth faffing around with a machine: It may be getting on, and you’ve tried many things to make it work better but without much success. Save your time and money: Replace/rebuild it instead.

Section 3: You’ve just been given a machine and you’d like to rebuild it.

Do so after checks; totally if you do: People give away machines because they’re old and/or faulty. Unless someone was feeling overly charitable and gave you a new or good-as-new computer, you can bet that there’s something not right with it.

- But remember; a lot of people are uneducated and/or non-computer-literate; so it might not necessarily be a hardware fault: It might just be a virus or corrupt operating system causing the problem possibly, so check to ensure that it’s not a software fault before doing anything else. Alternatively you might just want to rebuild it anyway, regardless of what the problem is.

In the case of it being the navigational computer from Noah’s Ark; or some such other ancient relic, rebuild it if you like the retro-style case (You could even do some retro-case-mods.), or use it as a boat-anchor: It’s probably too old to bother with, and you’ll just end up with extra hassle.

Finally -  Section 4: You’re just an ultra-geek who likes to stay on the cutting-edge.

You don’t need to be reading this article. You probably know what to do better than I do.

Just one thing I’d like to ask you though: Has anyone actually constructed a computer that really does do the washing-up? If yes; please sell me the blueprints.

Anything you’d like to add to the above? Disagreements, agreements, commendations, awards, whatever? Please comment below.