I replaced the BIOS battery in my A8V-VM. Then mobo won't start. The green 5VSB LED lights, then I press the power
button, but it isn't start. I try with three PSU, try clear CMOS, but computer isn't starts. I read on other forum, that, this was
an other man's problem too. He's solution:
-RAM out.
-PSU switch on, while take out the battery, press the power button,
-PSU switch off, wait... switch on, press power, button without battery and then, it's working.
-while the mobo run, put in battery.
Sounds like you either got the wrong battery or the battery that you got needs charging , how long has the battery been in there. Also the battery you got may be defective and you might need to get another one.