I run Ubuntu/Windows dual boot. Last night I started the upgrade to Ubuntu 12.04, and my computer has not worked since in either Windows or Ubuntu. Here's what I got when I rebooted after the upgrade, and continue to get every time I boot:

• Gets to GRUB screen OK.
• Choose Ubuntu -> black screen or crazy purple lines. At first I assumed something went wrong with the upgrade (often happens).
• Choose Windows -> works fine, I log in, but soon after that the graphics freeze (sometimes with purple artifacts). The keyboard and mouse (both USB) also lose power at the same instant, and none of the USB ports have power to them. This happens sooner or later every time I boot. Update: the HDD also appears to lose power at the same point.

I have tried a live CD, but my computer refuses to boot any CD even after disabling all other boot options in the BIOS. I have disconnected everything except keyboard, mouse, graphics card with one monitor, one RAM sick and HDD; no change. I also took the little battery out to reset CMOS.

I am pretty sure no matter how wrong the Ubuntu upgrade went, it wouldn't cause the above symptoms in Windows. So the only explanation I can think of is that a hardware failure occurred at the same time. Some possible causes of this I can think of are:

• A couple of days before this, I added a third screen (which worked fine).
• About a week before, my house lost power in a storm (no ill effects over the past few days though).

What can I do, other than buy a new motherboard/CPU and hope it works? Unfortunately I don't have another box to swap parts into to test at the moment.