Keyboard failure after startup (thunderstorm)

Bad thunderstorms last night. Heard a very sharp crackling sound outside the front of our home. My computer that I was working on at the time went down. Turns out cable modem got fried, as did the power supply for my computer. No circuit breakers tripped. Lights did dim a little. Everything else seems fine. We had all computer, printer, cable modem, etc parts on surge protectors or ups+surge protectors. BUT, turns out, my honey did not plug the phone line into the surge protector. He connected it directly to the cable modem. He said something about it degrading the signal if it went through the ups. :Hmm:  So maybe that's where something leaked through.

Long story short, I diagnosed the power supply was bad by using a multimeter and finding that all but two pins (green and purple wires) were no longer giving power. Got a new one this morning and installed it. Not exactly sure what happened after this, but when I turned everything on, my motherboard's amber led light was flashing slowly, like with the bad power supply. Nothing powered up (no fans, beeps, etc). Tried couple times. Then while I was sitting there, reading tech support sites on my cellphone, the cpu and case fans turned on for a second and then turned off. I kept trying the power button, and eventually my computer started trying to boot up, but would shut itself down. Kept trying and eventually the computer booted up and got all the way to windows logon. I was so excited until I realized the keyboard wasn't working. Rebooted, saw the lone "keyboard failure" during bootup (before the Dell logo? Or was it right after?).  Ugh, what a letdown.

Other details: have only wired keyboard and mouse plugged into any external ports (tried various usb ports on front, back, and top). Hard drive is plugged in, but CD drive is not. Keyboard works on other computer. Keyboard lights never turn on on this broken computer (XPS). Found on this website that people recommend taking out the cmos battery and clearing CMOS with the RTCRST jumper. Tried that. My computer used to go into Dell Diagnostics (I guess since I hard booted after it got to windows logon) on bootup, but now it just stops earlier with the "keyboard failure" message followed by BIOS being reset, etc., press F1...

So, any other ideas? Is my motherboard messed up? Is it safe to assume my hard drive and graphics card are still good? Good grief, I haven't been checked my NAS to see if my backups are safe. And of course I have customers waiting for me to fix my computer so I can finish their work.