Fujitsu siemens amilo d 7830

Sounds like you have an exhausted battery. Even rechargeable batteries must eventually be replaced when exhausted.

Try removing the battery and booting the laptop while plugged in. If it works, the battery is exhausted and you'll have to get a new one.

If the laptop still doesn't boot with no battery, and you don't hear the whirr of the hard drive powering up and starting to spin, then you have a boot problem.

Try to use a boot floppy, or at least try to boot with the
drive installed/attached to see if the laptop tries to access it.

You can also look for the reset switch, sometimes an innocuous hole
on the base or rear of the laptop - you stick a pen or paper clip in
it.
Remove any RAM upgrade chips. Frequent source on boot failure if they're the wrong size, speed, or chip config.

- this will take it back to the default device settings, in case you changed something that didn't take hold until you tried to
re-boot.

From the manual:

The notebook is prevented from booting by a disk in the floppy disk drive.
Check whether this floppy disk is a system disk. Remove the floppy disk.
Operating system files may be damaged or missing.
Boot the notebook with a system floppy disk, via the floppy disk drive.
i If the operating system is reinstalled, all data created up to that point will be lost. Make regular back-up copies of your data.

Some laptops have an initialize mode - you press down some keys while booting to reset the setting back to default. I'm not sure what those are in your laptop, but you can check in your manual, or in the store you bought it in.

Good luck

no solution yet....but if I take the battery out and just use the power supply it will boot normal ....will not boot with battery in....if I put it in while computer is on....it freezes up