qemu-system-i386 does not work

I am using QEMU 2.1.0 on a Slackware 14.1 operating system (with Linux 3.15.8).

I run QEMU like this:
$ qemu-system-i386 slackware-14.1-install-dvd.iso
I have also tested with the "-enable-kvm" and the "-m 1000" options.

And QEMU is does not work.
I mean, after 10 minutes, nothing is displayed on the screen, I am not able to see the Slackware installer.