strange windows behavior after OC?

My friend and I tried to OC his computer. He has the same rig as me, but stock heat sink. The OC did not go well (meaning we couldnt get anythign stable).

After these attempts, windows pauses for about 30 seconds before going to the blue "welcome" screen. It then plays the windows chimes while the "welcome" screen is still on display and after about 10 more seconds it loads windows normally.

Anyone have any idea what we screwed up? I changed all settings back to default and we didnt change any windows settings. This was not a problem before. His setup is the same as mine except he has stock HS and fan.

I've encountered simular issues and I think it has to do with corrupting the boot file when the oc fails. One way to correct it is to use 'system restore' and return your computer to an earlier state, or use the "Repair" option under windows installation program to rebuild your installation and boot files. I've had mine totally corrupt to the point of no return on a failed OC. That's why it's recommended to OC slowly and test between each step. It's also highly recommneded to create a back up copy of your boot drive, if nothing else, before undertaking an overclock. Hopefully you created a 'restore point' prior to OC'ing and the fix will be as simple as restoring to that point or an earlier point created automatically by Windows.
Good Luck!