Okay, first of all don't sweat it too much. This is a pretty common problem with Windows. I have never heard of a problem being fixed by leaving your computer off for 24 hours, so I wouldn't recommend that one.
My first instinct would be to re-install Windows. You would need to set up your "Boot Sequence" to boot from the CD. When prompted, you could choose to re-install Windows over the existing operating system. NOTE: ENSURE YOU HAVE ALL DRIVERS FOR YOUR EXISTING HARDWARE! It will take a few moments, but this should fix your issue.
You could also choose to "Repair" your Windows installation. This works okay, if the problem is damaged file. I haven't really seen this option work in too many cases.
The final option is to remove your partitions, format the drive, and re-install Windows. This is normally what I do, because it saves time with troubleshooting. The main drawback to using this method is that you lose everything on the harddrive. If you choose this option, please boot to safe mode first and back up any pictures or other files that you don't want to lose.
If you are unsure how to do any of this, please PM me. I will be happy to walk you through it.
make sure you have all the drivers installed for all the components inside your computer especially sata/IDE, unless you switched the HD out from another computer (i tried doing that today, and the same thing happened. i'lll just end up deleting all the drivers and mobo software before I switch it permenetly.)
If you didn't understand a word i just said do what Navyones said.
so far thanks a bunch guys and yeahh i know what you mean daversinger. lol