Check your soldering points on the LPC. There are two pins on there that if they are not making a good enough connection will cause the problem you are having so it could be just that your soldering wasn't perfect, but good enough for it to work when things are just right. I believe they are the 8 and 9 pins, not sure though but I do know they are on the LPC so just check that. If they look a little "iffy" at all, just desolder and re-do the pin header, it only takes a few minutes to do and it will most likely solve your issues. If however, your M$ dash doesn't boot with the chip off and hard drive locked, your gpu may have died, in which case you need to get a new mobo. Hope this helps!
Oh and don't forget if this helps you out to help me build my rep. on these boards by using the little button to the left to add to my reputation