It doesn't say "load drives", it says "load drivers". You must load drivers for the storage/RAID controller. Which controller do you have? Some must have RAID configured before any drives can be seen.

Sorry for My mistake "load drives", when I select load drivers, the window appear and saying please insert media (CD), and I don't know about controller, please help me in detail.

You can find out which controller by watching during POST for a CTRL prompt for the PERC (PowerEdge Expandable RAID Controller).

the PERC is PERC H310, when i enter to PERC H310 adapter BIOS configuration utility, under PD Mgmt all four hard disk were online, please let me know what i should do more.

Ok, what RAID level? 1, 5, 10? You need drivers for that controller.

You need drivers for that controller.

Download the "hard drive" version of the RAID drivers:

http://www.dell.com/support/home/us/en/19/Drivers/DriversDetails?driverId=XYPYC

Run it to extract the contents, the copy the contents to a flash drive. When Windows finds no drives, click the Load Drivers link, browse to the location of the driver files above and load them during the installation.

The RAID level is 5 and I create a virtual drive from four physical drives that I have it, but still when I am trying to install windows server 2008 standard r2 still there was no drive to select for installation.

I downloaded the hard drive version of the RAID drivers that you mentioned from link, then i extract the contents and copy the contents to a flash drive. 

during windows installation i click load drivers then browse the location my copied file (Drivers then XPYC) after that PERC H310 Adapter (C:\Drivers\XPYC\Percasas.inf) appear on window then i click next after this an error appear that the (C:\Drivers\XPYC\Percasas.inf) could not be installed, contact your vendor for updated driver.

You can try an older version:

http://www.dell.com/support/home/us/en/19/Drivers/DriversDetails?driverId=4R5XT&fileId=3413987313&osCode=&productCode=&categoryId=SF

Or you can try updating the H310 firmware. Or both.

I also try this, but still same error as above.