Restore to factory settings on Windows 7

Hello everyone. 

I would like to restore my Latitude E6510, running Windows 7 Professional 64bit, to its factory state.

When I bought it I noticed there are two hidden partitions, one is Recovery, the other one has no name (but in some programs it`s called OS). So there were those two hidden partitions, and one large with something like 450GB. As I do a lot of photo and video editing, I wanted another partition or two for those types of files (and documents, music...etc.).

I didn`t want to use some kind of software that would shrink the large partition into a smaller one, so I did a manual reinstall of Windows (I must have done it near 100 times already, so no problem there). In the windows setup I configured my partitions. ! I did not erase any of the two hidden partitions !

When the windows was finished with installing, I went to Computer Management (in Administrative Tools) and formated my partitions. After a while of using the laptop I noticed that the partitions I have made are not big enough for my demands, so I again wanted to resize them. I backed-up all my data on a removable disk, and wanted just to resize two partitions. Resizing was not possible because I could not delete those two partitions, and I noticed the disk was dynamic. 

So I converted it to Basic. After the conversion the two hidden partitions became visible. ! I did not erase them or change anything on these partitions ! I now wanted to resize my partitions but I was not able to do that, as I have erased them, and upon creating new ones the Computer Management would say something like "You have reached the maximum number of partitions with this type of disk". In that moment I wanted to throw the bloody notebook out through the window. Once again I did the conversion, and then was able to create new partitions. The two partitions were still visible, so I have hidden them and deleted the Letters that were automatically assigned to them.

Again, after some time of using the notebook, I wanted to use the Latitude ON function. So I installed the Reader 2.1, and found out that it does not work, something related to encrypted partition bla bla bla. Searching for a solution I came across a topic about restoring your dell to factory state. So I followed the instructions.

I press F8 after the boot, and then select Repair Your Computer, sing in, and then I can choose how to restore the computer. So I click on the last option (the icon is the same as on the Dell Backup and Recovery Manager), it seems like something is working (as I can see the circle on the mouse pointer rotating), but after 10 seconds it stops, and nothing happens.

It seems to as the Dell BRM has lost the path to the RECOVERY partition, I am just guessing that. Can anyone help me with this?