I just bought a gtx 1070 for my current system that was currently using a gtx 970, but now all my computer does is turn on with no signal going to my screen. I put back the 970 and it boots up fine, so everything still works.
i7 2600k
Msi p67a-gb65 (B3) Bios 1.j0
1000w psu
i7 2600k
Msi p67a-gb65 (B3) Bios 1.j0
1000w psu