How do I check the raid configuration on a PowerEdge T310

Using the OpenManage Server Administrator software - under Storage, Controller/PERC, Virtual Disks.  Which OS are you running?

You might also be able to deduce the configuration by finding out your RAID controller (should be listed under SCSI/RAID controllers in Device Manager), knowing the number of physical disks installed, and knowing the number and size of "disks" that Windows is currently using in Storage Management.

I have four 1TB internal disks and windows see as 1TB.

Sees what?  Attached to what controller?

Sees only ONE 1TB disk total?  That would mean that not all of your disks are being used.

Sees all four disks, each as 1TB?  That would mean that you are not using RAID at all.

Install OMSA:
http://www.dell.com/support/drivers/us/en/04/DriverDetails/Product/poweredge-t310?driverId=V1JDD&osCode=WS8R2&fileId=3365593125&languageCode=en&categoryId=SM

Download and run the file to extract the contents, then run C:\Openmanage\windows\setup.exe.  Add yourservernameoripaddress:1311 to IE's Intranet Zone with IE-ESC disabled.