Call Screener W7 is software that blocks unwanted phone calls. It runs under 64-bit Windows 7, and requires a dial-up modem that has voice and caller ID capability to be installed on your computer. (Note: Call Screener uses only the voice and caller ID features of the modem -- there is no need to "dial-up" anywhere.) When a call is blocked, Call Screener speaks the message contained in the ZapMessage.wav file to the caller. An example ZapMessage.wav file is included in the kit that comes in the download. A separate built-in anonymous caller rejection message instructs the caller how to remove their call blocking. Documentation is also included in the kit. Modems that I've tried and have worked well under 64-bit Windows 7 are the HiRO H50113 USB external modem, and the HiRO H50006 and Rosewill RNX-56AG PCI internal modems. I think the TRENDnet TFM-560U USB external modem may also work, but since I haven't actually tried one, I can't vouch for it. I've included a driver in the kit that supports both caller ID and voice for the HiRO H50113.