Hi, I hope you are well. I have a problem with my Mac-pro early 2008. It has been running sweet for aons. I have had to do bits of maintenance frame time to time. When I power up the Mac, get a high pitched squealing noise like when you let out the air of a balloon to make it squeal. The my Mac won’t always boot. Occasionally it will re-boot intermittently once the squealing has stopped. I replaced my old hard drives with new ones about two years ago. Can you shed any light on my problem? Kind regards, Reuben