I have an old Gateway GT5692 that came with a Foxconn RS780 Bengal mobo. I was very limited on money for upgrade so I purchased a AMD Phenom II X6 1045t as a replacement for my Phenom I X3 8450. Both are 95 watt cpus.
Officially my mobo only supports Phenom I cpus but saw online that as long as the bios was up to date it could handle a phenom II and may say unidentified cpu but still work.
Now PC starts lights, fans etc go on but can't even get into bios and nothing shows on screen either. I just was on the computer 15 minutes earlier.
I went back and checked all of my connections to no avail.
NEVER try to force a CPU series on a mobo that doesn't officially support it, especially if you have an OEM pc.
I'm afraid that you have to either :
Get back to old CPU .
start a new build because your mobo -even worse- supports DDR2 memory only, so if you want to get benefit from your new CPU you'll have to get new mobo & ram.