The whole drive will be re-imaged. You will lose everything on the drive that you added after you received the computer. However your factory image partition might not work if you have repartitioned the drive. You'll need to reinstall from disk if that's the case. Directions for all types of reinstall are HERE.  The D drive is the factory image-mistakenly named Backup/recovery. If you did use it for backup or added to or changed it in any way, it will not work.  
I have Dell inspiron 1525, and Windows vista Home Basic. I just wanted to do the Factory Image Recovery to solve some problem. Will it delete the data from only primary drive(C drive) or it will delete all other data from the seconadary drive as well (like E ,F etc.) When i bought the laptop there was only one Two partitions available C (main partition) and D( Back up drive). I just did the partitioning of the Drive C into E & F. And i have some stored personal data in these drives. Shall i need to keep the back up of the all the Data available in the E & F as well or it will only delete the data from C only? Pls Help.
Dell Factory Image Recovery- will it delete the data frm secondary drives?