If the system BIOS (F2 at powerup) still recognizes the drive, remove the drive, mount it in a 2.5" SATA USB 2.0 case and attach it to a working system to see what you can still read.

If the system BIOS does not see the drive, it's beyond home recovery - you will need a data recovery professional.  That won't be inexpensive - in the US, such recovery routinely exceeds $1,000 just for a basic job.

hello EJN63, thanks a lot for you reply and help.

I'm very sorry but unfortunately I do not know what you mean by still recognizing the drive, when I tap F2 at powerup, i get the following information:

bios version: a04

product name: inspiron N5010 (looks like i got the model wrong in my first post, sorry)

service tag:

asset tag: none

cpu type: intel (R) core (tm) i3 CPU   M 350 @ 2.27GHz

CPU speed: 2261 MHz

CPU id: 20652

CPU cache: L1 cache : 64KB L2 cache: 512KB, L3 cache: 3072KB

Fixed Hdd: wdc wd3200bevt-75a23to (320gb)

sata odd: plds dvd+/-RW ds-8a4s

esata device: none

ac adapter type: 65 w

system memory: 3072 mb

extended memory: 640 kb

memory speed: 1066 MHz

Thanks a lot for your help :)

Looks like the system does still recognize the drive.  Remove it, mount it externally, attach it to a working system and see if you can recover your data.  The external cases are inexpensive in the US -- $10-20 or so.