Why Warning Signs Get Missed
Computer performance degrades gradually. Unlike a car tyre blowout or a broken screen, most hardware problems unfold over weeks or months — and because the change is incremental, users adapt to it. A laptop that takes 45 seconds to boot instead of 25 seconds doesn’t feel broken; it just feels like “how it is now”.
This slow drift towards failure is exactly why the warning signs get missed. And it’s why most of the computers we see for urgent repairs were showing signs months before they actually failed.
Sign 1: The Computer Is Slower Than It Used to Be
Progressive slowness is the most common early warning sign — and the most commonly ignored.
A computer that’s slower than it was 12 months ago has changed. Something is different. The most common causes:
- Storage degradation: A hard drive developing bad sectors slows all disk operations. An SSD approaching capacity or showing early wear slows read/write speeds.
- Thermal throttling: Dust accumulation in vents and fans causes the CPU to reduce its speed to avoid overheating. The computer feels sluggish because the processor is deliberately running below its rated speed.
- Malware: Background processes consuming CPU and memory without your knowledge.
- Startup bloat: Software accumulated over years loading at startup, consuming resources before you’ve done anything.
A PC health check identifies which of these is responsible — and distinguishes between something that needs fixing and something that needs replacing.
Sign 2: The Fan Runs Loudly and Often
A laptop or desktop fan that’s running at high speed constantly — particularly when the machine isn’t doing anything demanding — is a thermal warning sign.
Computers manage heat by measuring CPU/GPU temperature and spinning the fan faster as temperatures rise. If the fan is always running fast, the machine is consistently running hot. This happens when:
- Dust has blocked the airflow path through the vents, trapping heat inside
- The thermal paste between the CPU and heatsink has dried out and is no longer conducting heat effectively (common on machines over 4–5 years old)
- The fan itself is failing and not spinning as effectively as it should
- The machine is working harder than expected due to background processes or malware
Chronic overheating shortens the lifespan of all internal components. It also causes thermal throttling, which explains the slowness described above. The two symptoms often appear together.
Sign 3: Unexpected Shutdowns or Restarts
A computer that shuts down without warning, or restarts spontaneously, is protecting itself from something.
The most common causes:
- Overheating: The thermal protection circuit triggers an emergency shutdown when temperatures exceed a critical threshold. If this is the cause, the machine often feels very hot to the touch, and the shutdown happens under load (watching video, running a demanding application).
- Power supply fault (desktop): A power supply unit that’s failing produces unstable voltages, which causes random shutdowns. More common on older desktops.
- RAM instability: Faulty RAM causes crashes and restarts that can happen at any point, often with a blue screen.
- Storage fault: Critical system files stored on a failing drive can cause crashes when the system tries to access them.
One unexpected shutdown can be a one-off. Two or three within a few weeks is a pattern that warrants investigation.
Sign 4: Files Taking Longer to Open or Save
If opening a Word document that used to open immediately now takes 10–15 seconds, or saving a file produces a noticeable pause, this points to storage performance degradation.
This is different from an application being slow to launch on first use. Files that take longer to open after the application is already running, or saving operations that stall, specifically indicate that the storage device is struggling to read or write reliably.
This is often one of the first signs of a hard drive developing bad sectors — the drive retries multiple times before succeeding or failing, which creates the delay.
Sign 5: The Battery Lasts Noticeably Less Time
A laptop battery that used to last four hours now lasts two hours hasn’t had an emergency — it’s degraded normally. But if the decline has been sharp (from four hours to one hour over a few months), it may indicate:
- Accelerated cell degradation from heat exposure
- A specific cell in the battery pack failing
- A charging or power management fault
Gradual battery decline is expected. Sudden or steep decline is a reason to get it checked.
Sign 6: Windows Update Keeps Failing or Hanging
Windows Update that consistently fails to complete is usually either:
- A storage fault (the drive can’t write the update files reliably)
- A corrupted Windows installation
- Insufficient free space
All three warrant investigation. A machine with a backlog of years of uninstalled updates is also a security concern — many updates patch known vulnerabilities that malware actively exploits.
Sign 7: Error Messages You Haven’t Seen Before
Any new error message — even one that seems minor — is worth noting. Specific ones to take seriously:
- “Windows detected a hard disk problem” — act on this immediately, back up first
- “Your PC ran into a problem” with storage-related error codes
- “SMART Failure Predicted on Hard Disk” in the BIOS
- Disk errors in Event Viewer (Event ID 7 or 11 from the disk source)
- “Disk C: is almost full” combined with performance problems
What a Health Check Finds
A professional PC health check goes beyond what these surface symptoms reveal:
- SMART data from the drive shows developing faults before they cause visible problems
- Temperature logging under load reveals whether thermal throttling is happening
- RAM testing identifies instability that doesn’t always produce obvious errors
- Security audit checks for malware, outdated protection, and compromised software
- Startup analysis identifies processes consuming resources unnecessarily
We give you a plain-English summary of what’s fine, what needs attention, and what needs fixing — with a clear quote for any work before we start.
If you’ve noticed any of the signs above, the right time to book a check is now — not after something fails. Book at our Putney workshop, call 020 7610 0500, or contact us.