If your monitor only has a vga input, you need a ps3 vga adapter. It would use the same output port from your ps3 as you'd use for component cables, and you don't really need hdcp - I think that's only necessary for watching blu-ray movies at full resolution, not for playing games on the ps3.
actually, you need a special ps3 to vga cable - hdmi is pure digital and can't be converted to vga (analog) with just a cable. the ps3 has a separate output that can take cables with composite, component, or vga (+3.5mm audio, I'm guessing).
As far as unplugging and replugging the cable, you could get a KVM switch, such as this: http://www.buy.com/prod/trendnet-tk-209k-2-port-usb-kvm...
You probably wouldn't need the usb ports of that, but you could still use the vga and audio inputs, and switching the monitor between pc and ps3 would just be a button push.
i dont know which features the ps3 requires hdcp for but from the little bit of research i did on the issue it appeared like the general consensus for no image displaying on screen was non-hdcp-compliance. if i remember correctly this affected even a few games, but its been a few months so i'm not sure.
The ps3 supports component and vga output, neither of which supports hdcp to begin with. If it refuses to show the image over hdmi with a non-hdcp-compliant display, I can believe that, but it's not the correct way of handling it. I believe a failed hdcp handshake is supposed to result in lower resolution (480i/p), not a complete lack of image.