I have a PC that I upgraded... or tried to upgrade the CPU today. The PC is about a year and a bit old, had an i5 cpu. I bought an i7 4790K LGA1150. When I put in the new CPU with heatsink and plugged it all in, the PC started for a brief moment, all the fans whirred accept the heatsink and then shut down, then repeated again fans (save heatsink) whirred and shut down. It keeps doing this till I power it down. I checked the cables, everything is connected correctly. I put back in the old i5 processor and used the new heatsink and every started up properly and booted into Win 8.1 64 bit with no issue.
The motherboard is a Gigabyte GA-B85M-HD3. I have a 750w PSU, 8 gigs of ram and a GTX 970 4gigs. Again, everything works fine with the i5 chip installed, but not with the i7. I have never replaced a cpu before, could this be a bad CPU? I tried looking for any updates to my BIOS but it looks like there is no updates for it and has never been any updates for it. So bad CPU or am I missing something?