Dell Inspiron 1564 system freeze. Again and again and again.

Yeeeeew. The system freeze just got worse (tentatively). And the soft buzzing sound from the AC adaptor is still there.

I got the AC adaptor and motherboard (yet again. I think it's the third or fourth now) replaced this morning by the service engineer. About 15mins ago, the system froze and emitted noise. BuzzzzzzZzzZzzzZZzzz.. Wanted to put a video up, but I'm having a hard time with AnyVideoConverter.

Can you guys do me a favour?

Put your laptop's AC adaptor to your ear and listen out for a soft buzzing sound. Both Mama and Hwey's HP adaptor is silent. I need more samples!

Thank you all!