PC works fine with 4GB of Memory but Monitor wont turn on with 8GB?

[Justink10]

I just recently bought a computer that came with 8GB of memory, and i installed windows vista 64 bit in it and it worked fine, but after i shut it down, and turned it back on, the pc goes on fine but monitor doesn't receive signal, but when i take out two sticks of memory and have just 4GB in, it works just fine. Does anyone know why this would happen and how i can run the 8GB i have?

 

[Tmagic650]

Either one of the memory sticks is bad, or a memory socket on the mothboard is bad. Try removing all the RAM and reinstall it, carefully making sure all the RAM is installed properly