No More HDD After Overclocking

Let me start this off by saying that i've decided to write this as an act of desperation. For the past 2 days i've been trying to overclock my intel core 2 duo e6750(@2,66Ghz) to 3,20Ghz. At first i said to myself that it will be pretty easy given that i have an OC option in my bios. So i RR my pc and enter the bios. Set the CPU frequency from 333 to 404 and voila, all seems to look good. So i save my options, restart and surprise! My HDD was no longer detected. But that is not the strange part. My pc has 2 HDD's; a Western digital 160GB IDE one and a Hitachi 320gb SATA. On the WD IDE i have Ubuntu linux installed. That HDD worked just fine after the OC and after booting into linux i confirmed that my cpu was overclocked to 3,20GHz. But for some reason the 320 Hitachi on which i had windows xp (which was my main os) was gone. Gone from the bios and gone from the Os selection page. The thing is everything goes back to normal once i set my CPU frequency back to 333. The HDD gets detected again, windows works just fine.
Now my question is, why in heaven's name is linux able to use the OC'd cpu with no problems and the windows HDD disappears completely?

Here are a couple of Screenshots of my bios CPU setting just to get a general idea of what im talking about:
http://img26.picoodle.com/img/img2 [...] 3edf6a.jpg

http://img02.picoodle.com/img/img0 [...] 506268.jpg