Member Avatar for denishinz

The following happened when I tried to turn off the laptop from Windows XP prompt.

After an extended period that the screen indicated Windows was shutting down, the blue screen memory dump came on briefly. Then the screen blanked and the computer restarted instead of turning off.

While restarting, it went through the bios routine and then the screen blanked and stayed that way. The CPU fan was running at high speed, also. I tried turning the laptop off but it wouldn't switch off even when continuing to push the switch in. So, I had to disconnect the AC adapter and pop the battery out to turn it off.

I plugged it back in and tried to power back up. Nothing except the LED showing that it's plugged into power.

I took the laptop apart and found that two of the heatsink posts had separated from the motherboard. I had repaired these about two years ago the first time they had separated. So, I repaired them again.

Still nothing, using AC or battery. I've also tried pulling out the CMOS battery to try to reset the BIOS.

Any ideas? Is it likely that the CPU is dead?

Thanks,
Denis

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For and — a focused troubleshooting checklist and likely causes for an older Presario that refuses to stay powered.

Start by isolating the power subsystem. Verify the AC adapter voltage with a meter (compare to the label) and inspect the DC jack for loose pins or burnt contacts. With only the adapter connected (battery removed) measure the motherboard standby rail (typically a small "SB" or 3.3 V standby line). No standby voltage usually means the adapter/DC jack or the power regulation stage is at fault; if standby is present but nothing else happens, the fault moves downstream.

Look for board damage where mechanical stress was previously repaired. Hairline cracks, lifted pads and broken vias around heatsink posts frequently interrupt ground or power planes. Inspect under magnification and use a continuity check between heatsink post grounds, nearby power components and the main ground plane. Small wire jumpers or conductive epoxy can bridge cracked traces when replacement boards are unavailable.

Rule out the embedded controller / BIOS before condemning the CPU. A corrupted BIOS or EC can produce spinning fans with no POST or lights that blink once. Recovery options for older laptops often require reprogramming the flash chip with a hardware SPI programmer or replacing the BIOS IC; blind reflashing can make things worse. If comfortable with soldering, identify the flash chip and consider a programmer; otherwise, a repair shop or a donor motherboard is the safer route.

Safety and triage: work with the battery removed and ground yourself. If basic checks (adapter, standby rail, DC jack, visible PCB cracks, shorted power MOSFETs) point to board-level failure, motherboard replacement or a targeted repair is usually more cost-effective than CPU replacement — CPU failure on these models is uncommon.

Member Avatar for denishinz

Symptom update - When I plug in the adapter cord (battery not installed) while holding the power switch down, the power and battery charge lights on the front panel momentarily blink on and then back off. No other signs of power. Is there thermal protection circuitry that somehow needs to be reset (BIOS?) before any other power can come back on and maybe not a problem with the CPU itself?

Thanks,
Denis

Member Avatar for pktboy

I wonder is the Compaq Presario 2720US a laptop or a desktop? I'm having a problem with a Presario laptop and wanted to know how I can reset CMOS? A BIOS flash went horribly, horribly wrong.

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