Data Recovery:- Remove the hard drive from the laptop and either fit it into an external USB hard drive enclosure or attach it directly to an interface on the motherbaord of a desktop PC. This will hopefully show up as a secondary drive and you may be able to read off the data.
Fixing Startup Problem:- You might do better making this a separate post under PC hardware - General Discussion, but here's a few ideas. I'll take it you've tried starting it on both mains and battery alone, and had no success.
Disconnect the mains adaptor from the laptop, and remove the battery. Hold down the power-on button for 10 seconds. Replace battery, plug in mains adaptor and try restarting laptop.
If no go, do the same (above) again, but don't replace the battery. Try powering up the laptop from the mains without the battery insitu. If that works, then suspect a bad battery.
ROGER - G0AOZ.