This is probably a common problem. I run the HDMI output of my HTPC through a 4:1 HDMI switcher box to the HDMI input of my Panasonic projector, i.e. no other monitor on the PC but the projector.

The problem I have is that periodically I lose the video output on the HMDI port and all I get is a blinking blue screen. This happens if I start up the PC with the HDMI switch not set to connect the PC to the projector, i.e. the PC doesn't see a monitor connected to the HDMI port. Understandable I guess, no EDID. However, there is no easy way I can get the PC to reactivate the HDMI port once this happens. I either have to restart the PC (which takes ages) or go to another machine on the network and VNC in to reactivate the HDMI port.

What I really need is some way of reactivating the HDMI port with a key press or whatever while I am looking at a blank screen.

Disconnecting and reconnecting the HDMI cable doesn't do it. I also tried this program which disconnects and reconnects the display:
http://thydzik.com/hdmion-a-solution-to-loss-of-dvi-video-epid-signal-on-hd-tvs/

Didn't work.

I know about the DVI Detective solution but to use this I would need to buy a DVI detective and cables to swap between HDMI & DVI and back.

Has anyone got any ideas on how I can overcome this problem?

HTPC: 3GHz P4
Nvidia 8500GT with HDMI o/p
Hauppauge HVR3000 tuner
Mediaportal & DVBViewer
Vista 32
Panasonic AX100 projector