Are you booting the installer and not running it from another OS?
If so then I'd download another ISO, try writing to flash stick using
Windows 7 USB-DVD Download Tool.
Boot under USB, Removable or HD's. Flash stick install is known to be faster.
You could have a bad DVD burn - if necessary to use DVD, burn with ImgBurn at 4x speed.
Unplug all other HD's and peripherals and try SSD in first SATA port in AHCI mode.