If it's like the DX4050 (which I have) you need Epsons software installed.
Did you install from a disc that came with it when new ?
If so look in "all programs" on your PC to see if it's there. Should be called "Epson Scan"
The scanning ability is excellent with comprehensive facilities.
If it's not there you should find it here,
Make sure you choose the correct operating system.
I think here are 4 items to install (assuming you have none on your PC) and there is a recommended order (there was for Vista.