A computer that restarts on its own is one of the most useful symptoms we see, because it almost always points at one of a small handful of causes. Random shutdowns are rarely random.

Here’s the order we work through them at the shop.

First: is it a restart, a shutdown, or a freeze?

The terminology matters. A restart means the machine reboots and you end up back at the login screen. A shutdown means it powers off and stays off until you press the button. A freeze that requires a power button hold is different from either.

Spontaneous restarts usually mean Windows or macOS hit a critical error and recovered. Shutdowns usually mean a hardware protection circuit fired (overheating, power glitch). Freezes usually mean software or driver trouble.

Cause #1: overheating

This is the most common culprit, by a wide margin. Modern CPUs and GPUs are designed to shut themselves off if they exceed a safety temperature — usually around 100°C — to avoid damage. The shutdown is sudden and complete, with no warning.

Signs it’s heat:

• The fan is running loud right before it shuts off
• The chassis or keyboard feels hot to the touch
• It happens during demanding tasks (gaming, video editing, big file operations) but not at idle
• It happens more in summer than winter, or worse when sitting on a blanket or couch

The fix is usually a physical cleaning. Dust accumulates inside the cooling fins until air can’t move through them, and once that happens, the fan can’t do its job. We open laptops every day that look like a sweater is wrapped around the heatsink. A proper cleaning takes about an hour and runs around the cost of dinner for two.

Cause #2: failing power supply

On desktops, a power supply unit that’s wearing out will randomly cut power to the system. It usually gets worse over time and is more likely under load. If your desktop has been chugging for five-plus years and is now restarting unpredictably, the PSU is the first place we look.

On laptops, a marginal charger or a bad battery can cause the same symptom — the system loses power for a split second and reboots.

Cause #3: failing storage drive

A hard drive or SSD that can’t read the OS files reliably will trigger Windows or macOS to crash and restart. This usually shows up alongside other symptoms: slow boot times, programs hanging, occasional file errors. SMART data tells us the story in about a minute.

If your drive is failing, the priority is backing it up before it dies completely. We can almost always clone a struggling drive to a new one and keep your install intact.

Cause #4: bad RAM

A failing memory module can cause restarts that look totally random. The Windows Memory Diagnostic tool catches most of them — it’s free, built in, and takes about 15 minutes. Search “Windows Memory Diagnostic” in the Start menu and let it run.

Cause #5: software, drivers, or updates

If the restarts started right after a Windows update, a new graphics driver, or a fresh app install, that’s your suspect. Roll it back. Windows has a built-in option under Settings → Update & Security → Recovery to undo recent updates.

Anti-virus software (especially the kind that came preloaded on a new laptop) is another frequent cause. We see PCs running three different AV products simultaneously, fighting each other.

Cause #6: bigger problems

Less common but worth mentioning: motherboard issues, swollen batteries pushing against the trackpad, liquid residue from an old spill, and (rarely) malware that intentionally crashes the system.

What to tell us when you bring it in

The most useful info: when does it happen? Always at startup? Always during games? Random throughout the day? Does the fan get loud first? Did anything change recently — new software, new hardware, a Windows update, a move to a warmer room?

Come See Us

If your computer is restarting on its own and the simple stuff hasn’t fixed it, walk it into our 9th Street shop. Most diagnoses are done within 24 hours of check-in, and we’ll show you what’s going on before doing any work. Mon–Fri, 10AM–6PM. (919) 314-3327.