This writing is not about outright fault, which is fairly easy to solve but about a system that is functioning but have a certain abnormality or intermittent fault.
If there are abnormalities in running a program or the system is running strangely unlike the usual as you know it, then something is not right. You could reinstall the offending program or if it is the system on the whole then the best thing to do, in my opinion, is to do a complete clean reinstall of the system. Yes, the OS and the application programs that are installed.
No doubt, it is good to know the problem that beset the system. But, unless you are paid to find it, it is best to do a clean install. This way you save a lot of time and if there is malware involved, it is surely gone unless it’s in the bios or somewhere in the hard disk. To get rid of those two previously mentioned annoyances, you have to reflash the bios and do a low level format of the hard disk respectively. You seldom need to do this. These are last resort if after a clean install fails to get rid of the problem.
If a system occasionally freeze or display that BOD, it is most likely hardware related. Dust collected over time on the motherboard could cause timing error, the contacts on the slots, cards and memory sticks get corroded or not enough cooling on the system especially the power supply unit.
A vacuum cleaner will suffice in sucking the dust off the motherboard but here in the tropic, the dust stuck and it is unlike what you see in a movie where they just blow off the dust. I had washed the motherboard a few times before. First I wet it, then sprayed bleach over it and after half an hour put it under tap and had water sprayed on it by closing the tap opening with my thumb. It was then left standing on it’s side a couple of days to dry. If you decide to try this, then it is at your own peril, I am just telling what I did.
Contacts get corroded over time and need to be cleaned. Usually I use alcohol but at times I do polish it with metal polisher and finish it with alcohol. It’s extreme but the shining contacts will remove any doubt about its performance.
Heat is another source to suspect. If a system is not properly cooled, after a period of operation it will become unstable. The airflow in the PC casing could be bad, the fan maybe reaching its end of life or the PC itself is situated in a place where the air circulation is bad. Blowing warm air will not cool the system sufficiently and the surrounding air will only get hotter. First to suffer will probably be the power supply because it is the hottest and had a mediocre cooling system compared to the one the CPU had. I had replaced a system in slim casing to a slightly wider casing (wider grille on the power supply). The PC is placed under the table in a small room. Although the room is air-conditioned there is not much cool air circulating underneath the table. It is sucking back it’s own hot air and the power supply had small exhaust grille. On another occasion, I had replaced a PC power supply twice in a short period of time. After the second replacement, I asked the owner what did he do with it. He said that he played game in a closed room. I told him to get it ventilated and had not heard from him since.
Besides this, you have programs that will test and check the hardware and the memory. I hardly use it anymore except for testing and checking the memory sometimes. The initial bios test is good enough and now some motherboards do include memory test option in their bios which is a good thing.