Wellcome Killj0y
As a rule it's best NOT to overclock your system whilst installing Windows. I'm guessing you are installing Windows XP but you didn't say
Set the system back to normal speeds and try again, you can allways overclock the system when Windows is up and running
I have found that Windows can be a little less forgiving when overclocking so it will be trial and error i'm affraid.
If it's just a formatting problem you can search around for boot cd's that have the format util's built into them or you can simply delete the partition and create a new one in the empty space. Some boot CD's to search for are Hiren's boot CD and Ultimate Boot CD- both of wich have all the tools built in you could need.
Got to say i love the pic the lik in your sig takes you to, excellent work!