So today my friend and I had upgraded my GPU to a gtx 970, we also added a new hard drive. After installing everything we booted up the computer and got the message, "Please select a boot device." This happened many times upon restarting the computer. It would only work seemingly when it wanted to, the sata cable and power cable were all plugged in correctly. I have already made a back-up on my HDD. Are there any suggestions other than a dying SSD?