error code 0x80070057 while installing W7

In the bios it finds the hd with the name P0:and here a long code

And without the HD it boots to BIOS in 2 sec and with HD I press F2 and then still like 10-30 seconds

When I changed AHCI to IDE in the BIOS it found the HD, so sorry for so many posts. I will run the long test now

When running the long test the test failed and said:
The Drive is not responding to commands. Check cables and drive power connection.

What should i do now?

Sounding more like a failing HD. You can try reseating it in its compartment underneath the laptop. If you google your exact make/model + replace hard drive you may find a video showing how to access it, or go to the Support Downloads webpage for your model PC to read the Manual or look at the Support pages for help on this.

Once you reseat the HD firmly then try the test again.

If it continues to fail then replace it. The best upgrade one can get now is an SSD which is lightning fast with prices falling now to around $50 per 120 gb if you search: Best deals of the day

Thankyou for al your help!
Now I'm going to buy a new SSD for my laptop and i have one last question.
Will the Samsung 850 PRO 256GB 2.5 inch fit in my asus n56vz?(my hdd is also 2.5 inch)
And do I just put the new SSD in and then install windows 7 and everything will be OK?

Yes, it's the same size so it should install into the drive bay just like the other one. If it needs something to take up space there is normally a cushioning pad included to make it fit snugly.

The only illustration I can find is page 64-5 of Manual here: Notebooks & Ultrabooks - N56VZ - ASUS

Well thankyou!
And I don't seem to see what you're seeing on page 73-4. Here it is something with bluethoot ?

pp 64-5.