PC keeps constant restarting

Hey everyone,

I’ve got a situation here that feels like a hardware failure.
Basically, when I power the machine up, I can get into the BIOS just fine. I can sit in there for 5 or 10 minutes without anything weird happening. CPU temps are hovering around 60 degrees.

The catch is, if I don't manually enter the BIOS, the PC just restarts before it even attempts to load Windows. It gets stuck in this endless loop—powering down and then immediately kicking back on.

I tried disconnecting the SSD to troubleshoot, and I managed to hit that black screen that says "no boot device," but as soon as I reset it, the whole thing went right back into that power cycle loop.

The rig is about 5 or 6 years old... running an i5-3350p.

What should I be looking at replacing?

Thanks.

This might be unrelated to the actual issue, but seeing 60C in the BIOS is pushing it... even if it's 90 degrees outside and you aren't running the AC in your office.

Honestly, you might just need to upgrade your PC 😬

But seriously—no joke here—you really ought to check out what’s going on with that fan first. It could just be choked up with dust and needs a good cleaning, or maybe the fan itself is actually dying and you'll need to grab a replacement...

I ran into this exact same headache—it all came down to dust buildup. I tried cleaning it out with a microfiber cloth and gave the fans a good blast with some compressed air, and honestly, everything ran perfectly fine for about two or three years. When the issue popped up again, I decided to go a step further; I repeated the cleaning process and actually took the time to swap out the thermal paste entirely. And you know what? It’s working flawlessly now.

So, I cleaned out the heatsink, swapped the thermal paste... and when I went to check the temps in the BIOS, they shot straight up to 100°C. I managed to boot into Windows just long enough to grab a monitoring tool, and yeah—it was sitting right at 100 degrees. It only stayed like that for a few minutes before things went south.

Now it’s even worse. I can't even get into the BIOS anymore. The monitor won't even get a signal, and the PC just keeps rebooting itself over and over...

Anyone have an idea?

I’m dealing with this exact same headache, and predictably, it always seems to act up right when I actually need to get some work done.

To give you the full picture, I have this old desktop rig that I bought a while back and subsequently beefed up with extra RAM and an SSD. Ever since those upgrades, the machine has been prone to these sudden, total system crashes—it just throws a bunch of purple nonsense on the screen and stays dead until I manually hit the power button to force a restart. Then, following a recent Windows update, things took a turn for the even more bizarre; now it either suffers those same crashes or simply decides to reboot itself out of nowhere. To top it all off, the whole thing has become noticeably sluggish, which is infuriating considering I’m not even running anything heavy—just some GNS and VMware for practice sessions.

I actually hauled it back to the shop where I originally picked it up, but they were completely useless; they couldn't replicate the issue at all. I even went as far as taking photos of the error screen to show them what I meant, but since nothing happened while it was sitting on their bench, they basically washed their hands of it. When I dig through the logs, I don't see any specific smoking guns, just a series of red "critical error" messages that offer absolutely zero descriptive detail.

Does anyone have a theory on what might be going on here? Could it be a failing motherboard? 😁

wearyraven41 said:I cleaned out the heatsink, swapped the thermal paste... then when I went to check the temps in the BIOS, it jumped straight to 100°C. I managed to boot into Windows just long enough to grab a monitoring tool, and yeah, it was sitting at 100 degrees. It only lasted a few minutes before...

Now it’s even worse. I can't even get into the BIOS anymore. The monitor won't even turn on, and the PC just keeps rebooting itself...

Huh?

Check if you actually seated the heatsink correctly and made sure the fan is plugged into the motherboard. Something definitely went sideways when you were putting the cooler back on...

wearyraven41 said:Hey everyone,

I'm dealing with an issue that feels like it might be hardware-related.
Basically, when I power up the PC, I can access the BIOS just fine. I can hang out in there for maybe 5 or 10 minutes without anything unusual happening. CPU temps seem to stay around 60 degrees.

However, if I don't enter the BIOS, the machine just keeps restarting before it even gets a chance to attempt loading Windows. It enters this endless loop—just shutting down and rebooting over and over again.

I tried disconnecting the SSD, and I actually managed to reach that black screen stating no bootable device was found once, but after a reset, it went right back into that power cycle loop.

The system is about 5 or 6 years old... running an i5-3350p.

What should I look at replacing?

Thanks.

Look, I recently opened my rig up to pull the GPU and blow out some dust, etc. Everything seemed fine when I put it all back together and plugged everything in. Then today, I picked up some new speakers, a mouse, and a keyboard. Suddenly, total disaster. Blue screen. I couldn't figure out what went wrong. After hitting that blue screen five times in a row, I started retracing my steps in my head. Before I decided to tear the whole thing apart again, I tried unplugging the keyboard, mouse, and speakers, then redistributed them across different USB ports, and suddenly everything worked perfectly. Maybe you might have misconfigured something too?!

Have you taken a good look at the motherboard components to see if anything actually fried? Usually, when capacitors give out, the PC starts resetting itself just to prevent a massive voltage surge from wrecking everything. You can technically tweak some settings to bypass that, but honestly, I wouldn't recommend messing with it. From where I'm sitting, if it’s refusing to boot entirely, you're likely looking at an issue with the Southbridge. Give those parts a thorough inspection and let us know what you find.

Repair guys can swap out those capacitors just fine, you just have to make sure the values match up perfectly.

Sent from my iPhone 8 using Reddit

Greetings.
I’m dealing with a PC issue. It shuts down immediately after startup, right when the motherboard logo pops up on the screen. I tried getting into the BIOS, but even that won't work anymore. Any idea what the cause might be or how to fix this? My USB drive with Windows 7 isn't being recognized either. Thanks in advance.

Try opening up the PC and checking if there’s just a massive buildup of dust inside—clean it out and it should run smoothly again. It might be overheating because of the grime; if that isn't the issue, then you're likely looking at some hardware failure...

Everything's been cleaned and tidied up. Applied fresh thermal paste to both the CPU and the GPU. Now, when I try to boot, it usually hits the motherboard logo and then just dies after about 45 seconds. Occasionally it'll let me into the BIOS, but the menu freezes out of nowhere. What am I looking at here? Power supply or the motherboard?

- Give it a shot by going into your BIOS and turning off that startup logo so it just shows "POST" instead. That way, you might actually be able to see exactly which step the system is hanging on.
- Try unplugging everything else connected to the motherboard—your DVD drive, extra hard drives, and those front panel USB ports. Take a quick look at the rear USB ports too, just to make sure none of the pins are bent or busted. Obviously, it won't boot without a Windows installation disk, but if it stops freezing, you'll know that specific device was the culprit.
- If you've got multiple sticks of RAM, try running the PC with just one at a time. Swap them out one by one until you find the specific stick that's causing the headache.

wearymason4 said:front panel USB ports

I ran into this exact same issue myself. It honestly took me several days of troubleshooting just to realize how incredibly stupid the mistake was.