|You may be experiencing a problem with your main battery, or it may not be being charging properly for some other reason.|
See response 1 in this:
Correction for that:
The jack in the laptop should move when you wiggle the plug in the jack.
should have been
The jack in the laptop should NOT move when you wiggle the plug in the jack.
The bios has probably got nothing to do with your problem, unless you attempted to flash the bios and that failed.
Bioses do not spontaneusly get corrupted otherwise. Malware that infects bioses is extremely rare these days.
A mboard/cmos battery that is too weak or dead will NOT cause your computer to not boot if nothing else is wrong.
Contrary to popular belief, it is extremely rare for ram that was working fine previously to go BAD, unless you have damaged it by something you did when installing or removing it, or unless it was damaged by some event such as a power failure or a power supply failing. Almost always, when you have a ram problem, it's either because the ram has a poor connection, or you have installed ram that is not compatible with your mboard's main chipset, or it's CPU's memory controller if that applies.
A common thing that can happen with ram, even ram that worked fine previously, is the ram has, or has developed, a poor connection in it's slot(s).
This usually happens a long time after the ram was installed, but it can happen with new ram, or after moving the computer case from one place to another, and I've had even new modules that needed to have their contacts cleaned.
See response 2 in this - try cleaning the contacts on the ram modules, and making sure the modules are properly seated:
For a laptop, you must remove both its main battery and AC adapter before you do that.
See your Owner's or User's manual for your brand name model, or the mboard manual for your model if you have a generic desktop system, if you need more info about how to properly remove and install the ram modules
Don't randomly try other ram modules - not all ram is compatible with your computer. In the worst cases of incompatibilty your mboard WILL NOT BOOT all the way with it installed, and the mboard may not even beep - the ram has to be compatible with the mboard's main chipset, or in the case of recent mboards, compatible with the memory controller built into the cpu.
There's probably nothing wrong with the ram modules that worked fine previously.
It is easy to test for incompatible ram that has caused your mboard to fail to boot.
Remove the AC adapter's connection and the main battery.
Remove all the ram.
Install at least the main battery, and connect the AC adapter if you want to .
Try to boot.
If nothing else is wrong, you will get no video but you will hear a pattern of beeps that indicate no ram is installed, or a ram problem.
E.g. for an Award bios or a bios based on one, that's often a beep of about a half second, silence for a half second, a beep of about a half second, silence for a half second, continuously.