A gaming PC that won't boot is usually failing at one of four stages: power delivery, the hardware self-test known as POST, display output, or Windows itself. Note exactly what happens when you press the power button: nothing, fans but no picture, beeps or lit diagnostic LEDs, or a Windows error. That symptom tells you which part to test first.
Most no-boot problems turn out to be a loose cable, a switched-off supply, a monitor plugged into the wrong port or a stale BIOS setting, not a dead component. Start with the cheap, reversible checks and work your way towards the expensive ones. This guide follows that order.
What happens when you press the power button?
Find your symptom in the table, then jump to the matching section.
| Symptom | Stage that is failing | First checks |
|---|---|---|
| No fans, no lights, nothing | Power delivery | Supply switch, wall socket, main power cables, power button connector |
| Fans spin for a second, then stop, and repeat | Power, a short, or the CPU power cable | CPU power connector, case standoffs, minimal test |
| Fans and lights on, screen black | POST or display | Monitor cable on the graphics card, reseat RAM and GPU, clear CMOS |
| Beeps from the case | POST error | Beep pattern in the board manual |
| A CPU, DRAM, VGA or BOOT light stays on | POST stuck at that stage | Reseat or test that component |
| Reaches BIOS, not Windows | Boot drive or settings | Is the drive detected, boot order |
| Windows logo, then restart or error | Operating system | Recovery tools |
Nothing happens at all: how do you check the power chain?
Work from the wall socket inwards. It sounds basic, but a switched-off supply or a dead surge strip accounts for a surprising share of "dead PC" cases.
- Confirm the switch on the back of the power supply is set to on, and the cable is firmly seated at both ends.
- Try a different wall socket without the surge strip or UPS in between.
- Look for a small standby light on the motherboard. If it's lit, the supply is providing standby power.
- With the PC unplugged, open the case and press the main 24-pin connector and the CPU power connector firmly home. Those 4 or 8 pin CPU cables are easy to forget.
- Check that the front-panel power switch lead sits on the correct pins, using the motherboard manual's diagram.
Technicians rule out a faulty case button by briefly bridging the two power switch pins on the motherboard with a screwdriver. If you're not comfortable doing it, skip that step. If the PC still shows no sign of life, suspect the power supply or the board. Swapping in a known-good supply is the quickest test. Our list shows a 650W supply at ₹3,000 to ₹5,000 and an 850W or larger unit at ₹5,000 to ₹8,000, indicative. Never open a power supply casing, because its capacitors can hold a dangerous charge. See failing power supply warning signs for the telltales.
Fans spin, lights are on, but there's no picture: what next?
This is the classic POST problem, and the fixes are usually simple. Work through them in order.
- Move the monitor cable. When a graphics card is installed, plug the monitor into the card, not the motherboard. The board's own outputs are normally disabled. Also confirm the monitor is set to the correct input.
- Reseat the graphics card and its power cables. Remove it, push it firmly into the slot until the latch clicks, and reconnect each power plug fully.
- Reseat the memory. Try one stick in the slot recommended by the manual, which is often the second slot from the CPU. Then try each stick alone.
- Be patient after changes. After new RAM, a BIOS update or a CPU change, some platforms, including AMD's AM5, retrain memory on first start and can show a black screen for a few minutes. Wait before concluding anything.
- Clear the CMOS. With the supply switched off and unplugged, remove the coin cell for a minute, or use the board's clear jumper or button. This resets BIOS settings and doesn't touch your files.
- Test without the graphics card. If your processor has built-in graphics, remove the card and use the motherboard output. If the PC then shows a picture, the card or its slot is the problem.
If you've recently moved or replaced the processor, look for bent pins in the socket on boards that use them. Don't press or straighten them unless you've done it before, because they snap easily.
What do beeps and debug lights tell you?
Many boards have four small lights labelled CPU, DRAM, VGA and BOOT. They illuminate in sequence during POST, and the one that stays on tells you where the process stalled. Higher-end boards show a two-digit code on a small display, and the manual decodes it. Your board manual is the authority here.
Beep codes depend on the BIOS maker. As a rough guide, repeated short beeps often relate to memory or power, and some long-then-short patterns relate to graphics. Many modern cases have no speaker at all, but a cheap buzzer can be plugged into the board's header. Our startup beep code guide goes through the common patterns.
It reaches the BIOS but won't load Windows: what should you check?
Good news: the hardware works. Now see whether the BIOS lists your boot drive. If it does not, reseat the SSD or its cable, and check whether a recent setting change hid it. If the drive is listed, check the boot order and the boot mode, since a firmware update often resets them.
If the drive is listed but Windows doesn't start, use the Windows recovery environment from a USB stick. Our guide to common Windows 11 errors covers the repair ladder, and the computer boot repair service handles stubborn cases. If the drive isn't detected at all, read why a desktop won't detect a hard drive, and remember it might be failing.
How do you run a stripped-down test?
When the cause isn't obvious, build the PC back from the minimum. It's the most reliable way to isolate a faulty part.
- Switch off, unplug and touch bare metal to discharge static.
- Remove extra drives, extra RAM sticks, add-in cards, USB devices and fan or RGB controllers.
- Leave the supply, motherboard, processor with its cooler, one RAM stick, the graphics card (or built-in graphics) and the monitor.
- Try to boot. If it posts, add parts back one at a time until it fails again.
- Work on a hard, non-conductive surface, never forcing a part into a slot.
When should you stop and get help?
Stop if you smell burning, see bulging or leaking capacitors, find liquid inside, or notice bent socket pins. Also stop if the PC keeps cycling on and off and none of the above fixes it. Our price list shows motherboard repair from ₹2,999 to ₹8,999, indicative, and a written quote follows a proper diagnosis. See gaming PC repair for how we help. If the machine is crashing after it boots rather than failing to start, read how to fix gaming PC crashes.
Frequently asked questions
Why does my PC turn on for a second and then shut off?
Common causes are a loose or missing CPU power cable, a short circuit such as a stray standoff behind the motherboard, or the supply's protection tripping. A stripped-down test usually reveals which.
Will clearing the CMOS delete my files?
No. It resets BIOS settings such as boot order and memory profiles to defaults. Your files stay on the drive.
Can a dead CMOS battery stop a PC from booting?
Usually it just resets the date and settings, but it can cause error prompts on some boards. The cell is cheap and easy to replace.
If there's no display, is my graphics card dead?
Not necessarily. Check the cable, the monitor input and the port on the card, and reseat the card. Test with built-in graphics, another cable or another monitor before blaming the card.
If your PC still won't start after these checks, book a free pickup. We'll diagnose it and quote in writing, and the ₹350 inspection fee is refunded if you go ahead with the repair.
