This does NOT make any sense......

I would pull the tv card out and try the video without it. You may have a device driver conflict. Get the video going before using any other accessory cards. If you get a signal, go into the control panel under "system" >hardware>device manager. If you find any marks next to a device driver, uninstall it and power down. Then try the tv card again.

Sounds like a bios setting and/or card display setting esp. if vid is being piped down the HDMI. That there tells you yes the mobo is working and accepting the card and giving you picture thru the HDMI. is it dual DMI? or VGA/DMI are you using the right plug on vid card to the monitor? if its dual dmi try swithching to the other. Another factor is the monitor res, can it handle the res the card is pumping out at that time, widows may not be adjusting it right and sticking with a high res since it was connected HDMI. Plug it in tv/hdmi and lower the res down to an older res such as 1280, save the settings and then try on the monitor again.

PS. I have the same kind of issue with my sound, everytime i use the HDMI the 5.1 surround it has stays at default and i no longer have regular system sound til i go back into devices and set it back to the 7.1 card for system(likewise if the 5.1 sound on vid card gets upgraded drivers it sets it to default as well)

Hmm.....yes to Dual DMI. the HDMI is via one of the DMI outlets with the switch the video card provided.

I tried both outlets and none of them works with the monitor.

It is strange because nothing else changed except for the MOBO, and it shouldn't really impact the video output , should it?

yes it can, due to the fact that it has to load a whole new set of drivers for the new hardware (ie chipsets, onboard sound etc..) which brings me to another issue. Is there onboard vid as well and you are just using a vid card instead? Again, your best bet right now would be to hook it up tv/hdmi and check the settings all the way around (ie bios during boot, then windows setting (make sure its listing the card as the primary/default vid adapter) and then lowering the res as stated saving those settings and reconnecting it to monitor then. Because like I stated if youre booting it up getting vid VIA hdmi then that shows the mobo is functioning.

so what you are saying is that the mobo works.

it is just a matter of tweaking the setting?

Did you do a format and fresh windows installation?

no. just swapped the mobo.

i mean it works ... only on my hdmi tv for some reason....

The boards have the same chipsets, a fresh install would probably solve it but is kind of overkill.

Do your TV and monitor support the same resolutions? Most monitors do not share the same aspect ratio as recent HDTV's unless you have a true widescreen monitor (i.e. 1920x1080). Connect both and try running through a dual monitor setup with the nvidia software, see if it recognizes the monitor and the TV then set resolutions accordingly. Or change to a resolution supported by the monitor while plugged into the TV. You can also try safe mode to see if it will kick to a supported resolution.

problem is that my graphic card stayed the same the entire time.

it worked on the other board....

Unless all chip drivers are exactly the same, I'd expect Windows issues with a MoBo change.

What really amazes me is that it works at all, even marginally; moving a HDD with an already installed OS to a different MOBO is just not feasible...

really? hmmm........well, the two Mobos are very similar. everything else stayed the same.

btw, problem solved. it was the monitor's dvi port.

Aaahh - the problem is that 'very similar' isn't 'the same' - usually, there are irreconcilable problems with what would seem minor issues like differing ACPI implementations, BIOS extensions, LPCIO differences - and it often turns out to be an object lesson in how many different BSOD error messages windoze is actually capable of throwing!

LOL yeah mon............

I guess unless its a video card or one of those external pieces, it is usually best to do a fresh install.

I was able to change my MOBO from a socket 754 DDR400 AGP with an amd 3200+ cpu to my new AM3 MOBO w a Phenom II X3 720 CPU and keep the SATA HDD with the OS by just doing a repair install of the OS off of the VISTA installation Disk (which reanalyzes and reinstalls all of the system drivers) and all I had to do afterwards was uninstall the old Nvidia graphics drivers and install the New ATI drivers and reactivate the license for the OS and the system has been completely stable (saved me about 2 days worth of reinstalling Apps etc. after the upgrade) - Only tried it because I didn't want to spend so much time reinstalling and adjusting all of my program settings and had read an article that said it was possible was shocked that things went smoothly and there have been no instability issues in just over a month of daily use