Hi,
Did the test you ran on the Hard Drive produce a 24 character ( 4 blocks of 6 letters/numbers ) error code?
If it did, this will be a Smart or Disk Self Test failure - in either case, it would indicate that the Hard Drive is failing and needs to be replaced. This is also consistent with the crashing and slow performance issues you describe.
If your notebook is still under warranty, contact HP ( with the 24 character error code ) and arrange to have the drive replaced - you can check your warranty status Here.
If you live in the US, contact HP Here.
If you are in another part of the world, start Here.
If you are out of warranty and would like a guide on replacing the Hard Drive yourself, please let me know - include the full Model No. and Product No. of your m6 series notebook - see Here for a further explanation.
Regards,
DP-K