My Compaq cq57 only shows charging light

Hi @donda80912

Try a complete power refresh in case it is a corrupted BIOS that is preventing the laptop from starting.

To do this all the power has to be removed from the motherboard, i.e. charger, the main battery and RTC (Real Time Clock aka cmos) coin cell battery which is located on the motherboard.

Unfortunately for you, in this laptop the RTC coin cell battery is located on the underside of the motherboard so it will be necessary to remove the motherboard from the laptop to be able to access it.

Here's the maintenance and service guide for the laptop. Go to p.71 (p.79 of 114 pdf) to view the procedure to disconnect the RTC battery from the motherboard.

When you have the RTC battery disconnected, measure its voltage. If it is <2.5V DC or if it is >5 years old, replace it. Search online for 646132-001 to find suppliers that suit you best. (examples only)

Next, reconnect the RTC battery (if it is OK) or its replacement to the motherboard, reassemble the laptop, reconnect the charger and check if it turns on OK.

If it turns on OK, then there may be a message stating that the date and time are incorrect. This is normal as the BIOS has been reset back to its default state. Once the date and time have been corrected, the message won't appear the next time the laptop is started. If any user definable BIOS settings were changed by you to suit your particular system requirements, these will have to be changed back as well.