Check the drives in the carriers ... if there is a set of holes further back, mount the drive there and see if they still go in all the way.
Recieved a donated Dell Power Edge R900. Naturally it didn't come with any harddrives, so we purchased some Dell 300Gb SAS 6 Gbps RPM10k Drives. After putting all of these in I booted to DVD and tried to install Server 2012 R2 but of course it didnt find any drives to install it on. After rebooting I went into the Utility Configuration (Perc 6/i Integrated BIOS Configuration Utility 1.11.52-0396). There I see a tree view of two things the first being "Controller 0" The thing under it says "No Configuration Present !"  When I go to controller and press F2 for Operations I get the box with three options (Create New VD, Reset Config, Foreign Config) However I can only select Reset Config. (Which for the sake of being able to do nothing else I have done) While in the Utility Configuration if I press F12 for Controller I see one entry: " Controller 0:PERC 6/i Integrate Bus 0x19 Dev 0x00 Fn 0x00 Slot 0x00"   So what should I do? Is this a driver problem? I figured since the config utility came up I was past that point?   Thank you
PE R900 Disk Configuration