The new computer I built in January can be a bit.. quirky, to put it nicely. One quirk is that after rebooting, the power LED will blink as long as the computer is on, until the power is cut to the motherboard. That was supposed to be fixed in the BIOS, so I attempted to upgrade.
That's when I found out another quirk is that if you press the wrong button during BIOS bootup, it can select a broken, preloaded overclocking profile that creates keyboard/mouse lag for DOS and other programs that interact on a BIOS level. Another side effect of this is to make flashing the BIOS impossible.
There is a long thread
about this on the motherboard manufacturer's forum, which eventually has you pull the BIOS battery for a while to reset whatever's gone wrong. I tried this earlier in the week with no luck. It booted up to the same lag and the same inability to flash the BIOS. I even tried booting a WinXP PE CD to run the windows flasher, but it just pegged the CPU until I killed it.
Today I tried again, this time disconnecting everything from the motherboard except the video card, a USB keyboard, and the USB stick with the BIOS flasher on it. I also made sure to erase all of the preset overclocking profiles. Success! No more keyboard lag (now I can use grub again!), no more power light flashing.
While this hasn't affected everyday use, it has made me more appreciative of the system I built last year using established technology rather than the bleeding edge stuff.