FAQ
TL;DR: 5 short beeps on POST indicate a CPU fault; "5 Processor failure" is the code. Check the CPU_FAN header, reseat recent hardware, and clear CMOS to restore display. This FAQ helps PC builders fix no‑display, loud‑fan boot loops fast. [Elektroda, Kolobos, post #17612859]
Why it matters: For PC builders facing no video with repeated beeps, decoding POST quickly narrows fixes and avoids costly mistakes.
Quick Facts
- POST beep spec: 5 short beeps indicate a processor error on Intel/AMI BIOS tables. [“AMI BIOS Beep Codes”]
- CMOS reset range: remove the CR2032 battery for about 10–20 minutes, then reinsert. [Elektroda, Miguel111, post #17612994]
- CPU_FAN detection: many boards halt with “CPU fan error” if no tach signal; connect the 4‑pin CPU_FAN lead. [“ASUS Motherboards — 'CPU Fan Error' Message”]
- PCIe power: a x16 slot supplies up to 75 W; add required 6/8‑pin leads for GPUs. [“PCI Express — Wikipedia”]
What do 5 short beeps on startup mean?
On most Intel/AMI systems, 5 short POST beeps indicate a processor error. The CPU failed initialization, so the BIOS halts. Confirm your board’s BIOS vendor, then follow CPU‑related checks first. This includes cooling lead, power, and CPU seating. [“AMI BIOS Beep Codes”]
My PC beeps five times and the fans go loud. What should I check first?
Check the CPU fan is securely attached to the CPU_FAN header. A missing tach signal often stops POST and ramps fans. Verify the cooler is mounted and the plug is fully seated. Then retry boot once. "Check that the CPU fan is securely attached." [Elektroda, Miguel111, post #17612940]
How do I reset the CMOS/BIOS without a display?
Use the battery method if no jumper is handy.
- Power off, unplug, and press the power button 10 seconds.
- Remove the CR2032 battery for about 10–20 minutes.
- Reinsert the battery, plug in, and boot; enter BIOS and load defaults. [Elektroda, Miguel111, post #17612994]
The issue began after I added a PCIe graphics card. Why?
Installing the GPU likely disturbed another connection. The OP reported beeps began right after seating a PCIe card. Recheck items you touched: CPU cooler lead, GPU seating, and GPU power connectors. Reseat the card until the latch clicks, then test again. [Elektroda, warszawiak96, post #17612797]
Can a loose CPU cooler cable really stop a PC from booting?
Yes. In this thread, reconnecting the CPU cooling cable resolved the beeps and no display. A loose fan lead can trigger protection and prevent POST. Ensure the plug is on the CPU_FAN header, not CHA_FAN. Then power on and test. [Elektroda, warszawiak96, post #17617170]
How do I use integrated graphics to troubleshoot no-display?
Connect your monitor to the motherboard video output (HDMI/DP/DVI/VGA). Remove the add‑in GPU or leave it unpowered while testing. This isolates PCIe card issues from CPU or BIOS faults. "Try to connect a monitor to it and turn it on again." [Elektroda, Miguel111, post #17612940]
Do beep codes vary by BIOS or motherboard?
Yes. Beep meanings depend on BIOS vendor and board firmware. One reply notes Intel lists five beeps as “reserved; not used” in some tables. Always check your board manual or the BIOS vendor list. "5 Processor failure (reserved; not used)." [Elektroda, Kolobos, post #17612859]
Where can I find official beep-code lists for my board?
Identify your BIOS vendor (AMI, Award, Phoenix) and open the vendor’s beep list. Many Intel/AMI tables show five short beeps as a CPU error. Use the manufacturer’s support page for exact mappings and notes. Bookmark the table for future builds. [“AMI BIOS Beep Codes”]
Could GPU power cause similar symptoms even if the code says CPU?
Yes, a disturbed GPU can still blank the screen. PCIe x16 slots supply up to 75 W; many cards also need 6/8‑pin power. If those leads are missing, the system may post but show no video. Always seat the card and connect power. [“PCI Express — Wikipedia”]
Is it safe to keep turning the PC on when it gives 5 beeps?
No. If the CPU fan is not detected, firmware can halt with a “CPU fan error” to protect the processor. Power down and fix cooling and power first. Then reattempt boot. Continuous power cycling risks heat stress and data loss on settings. [“ASUS Motherboards — 'CPU Fan Error' Message”]
Will clearing CMOS erase my files or Windows?
No. Clearing CMOS only resets firmware settings like boot order, fan curves, and memory timings. It does not touch disks or Windows files. You may need to reconfigure time and SATA mode afterward. Save current settings before clearing, if possible. [Elektroda, Miguel111, post #17612994]
