Power up, no boot, no beep shortly after recent Windows Update

I heard that the latest Vista x64 Windows Update has been giving people problems, but I thought it was limited to certain HP laptops. Maybe my problem is unrelated, but here goes the description.

By the way, I have searched the forums for very similar problems. None of the solutions (except replacing stuff) work.

I installed the updates on Wednesday. Right after the restart, my Windows Explorer started crashing whenever I opened Windows Update (and sometimes when I opened up the System properties).

I thought I would deal with it later and turned off the computer. Upon turning it back on in the morning, I started getting crashes right when the Windows logon screen would appear. I tried again, another reset.

I tried Safe Mode with networking. Reset. Safe Mode with Command Prompt. Reset. Safe Mode. A very very long loading screen. Reset.

This was followed by a regular boot (the computer didn't even ask me if I want Safe Mode), and Vista boots. I happily logon, everything seems to work fine. Then I got a BSoD. It froze when dumping the memory reached 100, so I reset.

After the reset, computer powers up, fans start spinning, even the HDD has the initial spin, DVD-RW powers up and opens tray, etc. I don't get any warnings, any beeps, anything on the screen (stays on sleep).

I start by changing the DVI-out slot on the video card. Then I unplug the network cable, the speakers, the webcam, the wireless keyboard set, then all the connections of the case from the mainboard (like usb, firewire, sound out), then remove power&data from the DVD-RW, cut the power to the video card, remove HDDs one by one until none is left, remove RAMs one by one until none is left, put some RAMs in randomly, remove mainboard battery for 30 secs and put it back on, remove and reinsert video card. All yield the same result: power up, fans spin, nothing happens.

What have I done? What can I do? Please help! I'm broke and in debt, and the school started this week!