HP ProBook 450 won't start.

[Theroadisalover]

My HP ProBook 450 has never had an issue. This morning tried to start. White power light flashing slowly then saw the yellow power light come on then back off. Then random lights on the keyboard began to flash erratically. Black screen the whole time and a high-pitched squeal barely noticeable but solid tone kept sounding off. Upon removing back cover there are three capacitors I believe that's what they are... Getting very hot. So then when I disassembled the covers to expose the motherboard I could see what would look like rosin the letter read that rossin could be present on the board from the manufacturing process. But couldn't help but wander if maybe a capacitor was leaking assuming that's what these things are. I don't believe the fan ever came on nor do I know if the hard drive was spinning it could have been. This machine is never had so much as a hiccup. So it's very strange. 1 end of the back cover was not snapped into place like it should be an I did wonder if someone tampered with it but can't get anybody to own up to it. Size of recover being dislodged just where the tabs don't log on one end that's the only thing I have to go by as a clue. I went ahead and check the memory to make sure they were seated properly. Besides the Rosen on the board there are no visible signs of damage. I'm going to wipe the board down for the rosin is and remove it to see if I can notice any obvious damage to the board itself. Ribbon cable and put it back together just enough so I can try to start it and see what it does again. Meanwhile if anyone has any clues as to put it might be please don't hesitate to drop me a line. I will check back here and document my findings and see if anything that's come up at that point. Any help you might be able to share with me. Please advise, thank you