HP — 3 long, 2 short beeps

HP's beep code for CPU failure. Unlike the graphics-subsystem code (3 long, 4 short) which is often thermal and fixable, this one usually means the CPU itself or the socket has failed.

What the code means

HP's BIOS plays three long beeps and two short beeps when the CPU fails to respond during POST. The BIOS sent its initialisation request to the CPU and got nothing back — so it stops, beeps, and waits.

This is one of the more terminal HP beep codes. Most graphics, RAM and storage failures have software workarounds; CPU failure does not.

What to try first (before assuming the CPU is dead)

1. Reseat everything

On a desktop:

1. Power off, unplug, hold power for 30 seconds.
2. Remove side panel.
3. Reseat the RAM (pull each stick, push back firmly until both side clips snap shut).
4. Reseat the GPU if you have a discrete one.
5. Reconnect both the 24-pin and the 8-pin (or 4+4) CPU power cable from the PSU. The 8-pin one is the most commonly forgotten — and a partially-seated CPU power cable can manifest as "CPU not functional".

2. CMOS reset

Find the CR2032 coin battery on the motherboard. Remove for 60 seconds. Replace.

The first boot after a CMOS reset is slow — the BIOS reinitialises everything from scratch. Wait a full minute before deciding nothing happened.

3. Check the CPU socket (desktop, advanced)

This requires removing the heatsink and CPU. Do this only if you are comfortable — bent socket pins can be straightened, but it is fiddly work and easy to make worse.

1. Remove the heatsink (heatsink screws in reverse numerical order, then lift gently).
2. Open the CPU socket lever.
3. Lift the CPU out vertically — never tilt or twist it.
4. Inspect the socket pins under bright light at an angle. They should form a perfectly even grid. Any pin that is bent, missing or bridging to a neighbour is your problem.
5. If pins are bent, you can try straightening with a needle or jewellery loupe. Realistically: this is a motherboard replacement.

If reseating did not help

You are almost certainly looking at one of:

• Dead CPU — rare but happens, particularly after a known overheat event or a power surge.
• Damaged CPU socket — usually from someone forcing a CPU in the wrong way during installation.
• Failed motherboard VRM — the voltage regulator that feeds the CPU has failed. The CPU is fine; it just is not getting power.

For a desktop with a socketed CPU, the cheapest test is to swap in a known-good CPU from another machine — if it boots, the original CPU is dead. If it does not, the socket or motherboard is the problem.

For a laptop, the CPU is soldered. CPU and motherboard are effectively the same component. Replacement is rarely worthwhile on machines older than four years.

Frequently asked

Read next

• HP — 3 long, 4 short beeps (graphics failure — often fixable)
• HP — 4 beeps continuous (power failure)