Alienware x51 R2 refuses to boot, dim light on power button

Hello everyone, I am new to these forums so forgive me if I happen to post this in the wrong place. I have an Alienware x51 R2, and it has been working flawlessly up until a few weeks ago. One day when I got home, it randomly shut off a few times as it seemed to be overheating. I later fixed this issue by cleaning out the inside of the computer. Today, I go downstairs to grab a drink only to come back to a fully powered off computer. I attempt to turn it on and nothing. The power button had a dim light on it. I have a power brick (Model: da330pm111) (333 watts) which i disconnected and then reconnected. The computer then turned on for a split second, turned on the LEDs on the side of the pc for a split second, turned on the dim light, and ran the cpu fan for about half a spin. And that's it. The dim light stayed on, and that was the only sign of life the pc was showing. The motherboard seems to have jolted on for a second as i noticed a blue light blink when i turned on the pc, but that's about it. I'm not really sure what to do about this. Is this a power supply issue from my power brick, or is this something more serious than that? The power brick does have a green light that stays on when plugged in. Any and all feedback is much appreciated.