Not sure where to post this.

[InsidAero]

I've been having trouble with my computer since last Christmas, or near there. It's been randomly shutting off since then -- earlier on, it gave a little warning by slowing down a lot before doing so. But as of late, there's no warning whatsoever. My older brother is a computer expert / professional and has replaced literally everything in the computer more than once, has reinstalled Windows more than once, onto multiple different drives (we thought the SSD he put in near Christmas could be the problem), tried multiple outlets since we thought that may be the problem and that didn't matter... And neither he nor I have any clue what the issue is. He took it over to his house to reinstall Windows yet again and it hadn't turned off once, despite being on the entire day. It also isn't overheating, we ruled that out long ago.

So, that said, does anyone have any idea what the problem could be?

[Salmon Trout]

If a computer problem happens after a move, or is cured by a move, from room to room or to another house altogether, then often the cause can be one or more components on the motherboard (RAM module, display card, other card, CPU) becoming slightly loose and the movement causes it (or them) to shake loose (or shake back again). Especially if it has had a ride in an automobile. I suggest making sure that everything that is removable is properly and securely seated. Check this with the power off and the AC power lead disconnected from the PSU. If the computer comes back to your house and works fine, you know you fixed the problem. if the computer works well at another location, but badly at your house, you may have dirty power, either at the particular outlet being used, or at the breaker board and you might have to consult an electrician.

[Geek-9pm]

Salmon Trout said:

if the computer works well at another location, but badly at your house, you may have dirty power, either at the particular outlet being used, or at the breaker board and you might have to consult an electrician.

That really  is possible.
Also, what else is different about your house?
Is it near High Voltages lines?
Next to a factory?
A lumber mill?
Next to a radio station?

If the power is 'dirty', a EMI filter might help.   

[patio]

We have no idea what components were replaced...nor what they are.

So at this point it's all guesswork...

[Salmon Trout]

has replaced literally everything in the computer

If that 'literally everything' includes the motherboard and PSU (which is what 'literally' would imply) then it isn't the same computer any more. Which makes me suspect the location in some way.

[patio]

Literaly...

[Salmon Trout]

A lot of people use 'literally' when they don't mean 'literally', like my colleague who said "It was so cold I literally froze to death waiting for the bus." I said "How come you're here now, then?", and he really didn't know what I meant.

[patio]

 

[Mark.]

to further the ideas already stated, it sounds like it works at one place and not at yours.
so my money would be on a peripheral - like keyboard, mouse, printer, something externally connected to the PC at your house that isn't at the other house.


I had a similar incident (worked here, didn't work there) and it was eventually traced to their keyboard, replaced that, all came good.

[Geek-9pm]

to further the ideas already stated, it sounds like it works at one place and not at yours.
so my money would be on a peripheral - like keyboard, mouse, printer, something externally connected to the PC at your house that isn't at the other house.

I had a similar incident (worked here, didn't work there) and it was eventually traced to their keyboard, replaced that, all came good.

I would agree. But did the OP really mean that the thing would work away from home? If so, there was no reason to replace co,opponents until the mystery was solved.
Yes, a mouse or keyboard and stall a computer. But it is so rare that it would begetter to fin d out what regally did the OP do with his computer.
A simple rule is to do every thing that is easy first. Like try another mouse, keyboard, printer, monitor or anything that you can unplug in twenty seconds. Evan  the power cable. In a few rare, rare cases the power cable prevented a computer from tuning normally. Hard to understand, be easy to check.

[Mark.]

@geek-9pm,
yeah, it's rare alright, I've only seen it that once in all my years in IT.
amazed the crap out me at the time.

[patio]

Meanwhile he's been abducted...

[InsidAero]

Meanwhile he's been abducted...

It hadn't been authorised last time I looked at it and expected it to maybe stay that way for awhile. And by "literally", I mean "literally", responding to your previous statement, which would include the motherboard and the PSU along with, as I said, everything else.

[patio]

So your saying every single component has been replaced and your still having issues ? ?