HP & QNAP Raid Recovery

HP RAID 5 ARRAY:

I am running a HP RAID 5 array fitted with 3 hard drives, which are used to store all the data from my PC. As the storage was getting full, I thought that I would add another drive to the array. This was supposed to be fairly easy, and I followed the array manual carefully. However, when I had put the fourth disk into the array, I ran the reconfiguration, and the PC started to show a number of errors across the screen, and then shut down. I turned on the system, but when I looked at the disks in the array, I could see that my data was missing. I have hundreds of documents and pictures which should have been on the array, but are now gone. I need to recover that data, a lot of it has great sentimental value to my family. I have looked everywhere for the data, but it seems to have been deleted or lost.

QNAP 4 DISK RAID 5:

I really need someone to help me with a serious problem. I have been running a QNAP RAID 5 array containing 4 WD disks, and which is connected to an Asus PC using Windows 7 OS. This computer is used mainly as a work PC and contains business plans, documents and pictures relating to the company. The computer put up a message saying that one of the disks has failed, and so I removed the disk which had the red light on the array, and installed a new drive in its place. The computer started a rebuild, but listed the entire array as failed. The new disk is not described as part of the array, and I am not able to get into the drives to view any of the data. I have tried another rebuild, but this also failed. Each time I turn it on it just requires a further rebuild, but I am not able to access the files to remove them before the rebuild starts.