I immediately suspected that the harddisk was damaged by the shock. Because I was afraid that the harddisk might fail altogether I created a recovery disk with the ASUS Backtracker software. Every major OEM has some kind of recovery software however I bet that most people never use it. You can either use a (16Gb) memory stick or USB harddisk for this backup.
|Backtracker software creating a backup of the factory recovery image on the laptop. I bet most people never do this.|
Next I checked the disk with chkdsk but it couldn't find a problem. Just to make sure that the harddisk was indeed the problem ran HD Tune Pro. They have a 15 days free trial of this software. With HD Tune Pro I was able to determine that the harddisk had a lot of bad sectors probably due to the heads of the drive crashing on the surface of the disk. There is only one conclusion possible. The harddisk needs to be replaced. I already ordered it and when it arrives I will replace it.
|HD Tune Pro performing an error scan on the harddisk. It already found multiple bad sectors (red).|