I have the DAC w/ the USB port, now what?

I bought an external hard drive for my music.
I got a Benchmark pre-amp DAC with a USB port.
I have not yet plugged the DAC into my PC.
Do I need another device or a software program to hear my music through my Hi-Fi system? If so, what software do you recommend?
It's a PC running Windows 7.
The most common choice for software to manage a music library is iTunes, but if you are a perfectionist about ripping your CD's to your hard drive, the iTunes error correction does not do as well as others. EAC (Exact Audio Copy) does a great job at ripping, and I think is still freeware. You will still need some kind of library management software though. I'm not a PC guy so I'll leave it to someone else to point you more specifically to alternates to iTunes, but as far as keeping your library organized, iTunes does a pretty good job. There may be something better for PC though.
Buy a Mac Mini and use Pure Music which makes Itunes think it is playing the music.
All you really need is good windows player software that's bit perfect. Take a look at Fubar Player... it's good and free. Also, the J River Jukebox... it's free and the J River Media Center... it's very good but costs $50.00. Use the WASAPI driver.

"Buy a Mac Mini"... Why???
You already have a computer and a good DAC!
Pkubica, all I can say is that I used to have a Windows server and used Fubar and Exact copy. I don't believe anything about being bit perfect, as the Mac, using Itones and Pure Music killed the Window/Fubar combo.
Tbg... if that works for you great! I never said it didn't. However, here we have a person who hasn't even plugged in what he has already. He has a computer and a DAC, let's give him a chance to try it out and get his feet wet first. Maybe the results of his current equipment and a Free solution will be just what he needs/wants.

This is a community where we all learn by trying. Please consider giving people a chance with what they already have and let them learn from it. Throw it all away and start over is not always the only option.

With all due respect...
Use free iTunes and $50 Rivers Media Player which lays over it and will play anything.