eMachines W3050 machine, AMD Sempron 3000+ Cpu (2 GHz, 333 MHz FSB, 512 KB L2 cache), 512 MB DDR SDRAM. I changed the FSB frequency in the BIOS to 200 from 166 (I know, stupid!) and now the computer won't do anything. The power light comes on when I turn it on, but the machine won't boot up. Anything I can do to get back to the BIOS so I can change it back?

You're going to have to reset the BIOS. Unplug the power cord, open the case & look for the motherboard battery. It's round & flat, about the size of a nickel. Remove the battery, wait a few seconds, pop it back in place. Close the case back up, boot the system, then immediately enter the BIOS & correct the settings. BTW, while you have the case open, blow out any dust...do NOT use a vaccuum.

Thanks. After posting my question, I found the user's manual for my motherboard online, and read about Clear CMOS. Duh! I knew that, I had just forgotten about it in my panic! So I moved the CLR CMOS jumper for 10 seconds, put it back where it belonged, fired everything back up, and I was back in business. Thanks for your help. PS I definitely need to blow the dust out of this beast!