Laptop fails to POST 50% of the time

I have a very nice laptop, a Compaq Presario C700 souped up with 2 GB of RAM (from another laptop of similar vintage).

Unfortunately, about half the time I press the power button, it fails to POST - it just sits there with the screen unlit and the hard disk not spinning up.

When it does boot, though, it works perfectly fine.

Anyone know what might cause this? Is it possible that the RAM (which should be of a supported type) disagrees with it in some strange way?

 

Hello,

From what I understand, the Compaq Presario v700 was introduced around 2007-2008.

If that is the age of the unit, perhaps the primary battery, the backup battery which provides a trickle of current to power the CMOS memory and RTC clock or both need to be replaced?

Otherwise, if both are working, I would think the power switch might have begun to fail (all mechanical parts will eventually wear out, after all), or even one of the internal capacitors.

Another issue might be from overheating. If you have not done so, you might want to open the system according to the service manual and clean out the inside to remove any dust and debris which may be reducing airflow and increasing temperature through the chassis.

Regards,

Aryeh Goretsky

 

Battery's okay. BIOS battery, not sure, but I haven't seen the BIOS lose time; so I think it's also okay.

The laptop was cleaned quite recently.

I'm pretty sure it's not the physical power switch, else how would the laptop power on? (I should pobably have been more specific - it powers on but does not POST.) Capacitors, I can't say.

In any case I put the original RAM back in and it hasn't done it again (yet)...

 

That was going to be my suggestion. I have two desktop computers that behave in a similar fashion. Reseating the RAM modules fixes them for a while.

 

Hello,

Did you add additional RAM to the computer? If so, perhaps the new RAM uses different timings than the old RAM, and neither RAM module shares a set of timings that match each others settings.

If that's the case, you may need to replace all of the RAM in the computer with identical RAM (same manufacturer and model).

Regards,

Aryeh Goretsky