T430 violently hisses and becomes unresponsive after being powered on for a bit

[interspersed]

Hi!

I have an old 1vyrain'd T430 running OpenBSD. Just the other day, out of the blue, the display started showing rapidly changing, random colors and patterns, and both speakers were blaring static/white noise. The machine didn't respond to the power button at all, and I had to resort to unplugging the battery. After plugging it back in and pressing the power button, the fan would speed up much higher than usual, and it would immediately shut off again.

Thinking it might be related to moisture (it was a humid & rainy day) I let it rest for the night in a dry, warm place and tried again today. The machine would boot into the bios, but after a minute or so, the same problem began, except just a black screen this time. Very loud white noise from the speakers.

I've already tried the following (carefully, and not all at once, lol):

- Take out both ram sticks and clean the contacts, put them back in and boot,
- Take out one of the two ram sticks and boot with just one,
- Take out the wlan card and boot,
- Take out and resocket the CPU and boot

All to no avail. Sometimes it doesn't post at all, just a black screen. Other times it gets to the logo and, after a few seconds, it starts hissing at me again.

As mentioned, the laptop has had the 1vyrain treatment with the bundled "unlocked" BIOS with advanced settings. Through these settings I had disabled Intel ME. I wonder if that has to do with it.

Any help would be greatly appreciated.