When clock battery is drained does computer have problems starting?

[cyclops123]

how to know when laptop clock battery needs replacing?

 

[IInuyasha74]

You mean the Bios battery right?
You will know it needs changed when your clock keeps resetting, but I think a lot of laptops anymore don't have them. They are constantly plugged into a battery and even when dead the system typically has a little power so they rarely drain completely.
This should have no effect on starting the computer what so ever unless the hardware settings are changing, but typically they stay at stock regardless.