AHHH Windows not working for NO REASON

Ok I was playing Rise of Nations on my computer, and everything was going normal. Then I decided to reboot and for some reason, it gives this error message before the bootscreen loads: ntoskrnl.exe failed to load. Please reinstall this file. WTF? I tried safe mode, last known good configuration ,and they do either do the same thing or just hang. Then I decide to reformat since my 100GB of media are on another partition, but when I insert the Windows XP Pro CD, it says Error 7 please exit setup or just hangs when loading Windows Executive. What the hell is happening here and what can I do about it?

Windows XP Pro SP1
AMD Athlon XP 2500 Barton
512MB DDR333 RAM
160GB Maxtor 7200RPM HDD/ w 8mb cache (Primary Master)
20GB Maxtor 5400RPM HDD (Primary Slave)
40x12x48 CDRW (Secondary Master)
Radeon 8500LE 128MB

I think thats all that matters....

ntoskrnl.exe failed to load. Please reinstall this file

Click to expand...

With your XP CD in the CD-ROM drive, and your CD-ROM set as the first boot device in the BIOS, boot to the Recovery Console and type...

expand cd-rom:\i386\ntoskrnl.ex_ drive:\Windows\system32

cd-rom is the drive letter of your CD-ROM drive, and drive is the drive letter of the HDD on which Windows is installed.

when I insert the Windows XP Pro CD, it says Error 7 please exit setup

Click to expand...

Give this a try...at the beginning of XP setup when you receive the "Press F6 to load SCSI/Raid Drivers" prompt, press F7 to bypass Advanced Configuration and Power Interface (ACPI) detection.

Also, what model of MB do you have installed?...and in your BIOS, do you have the option to enable/disable ACPI? If so, is it enabled or disabled?

How do I boot to the recovery console? Thanks.

My Motherboard is a Biostar M7NCD Pro Ver 1.1

Oh, and ACPI is enabled.

Insert the XP CD into the CD-ROM drive from within the BIOS, and while there...change the boot order so that the CD-ROM is the first boot device | When the "Welcome to Setup" screen appears, press R to start the Recovery Console | When you're prompted to do so, type the Administrator password (if the Administrator password is blank, just press ENTER).

Ok I had to leave for a few hours, and when I came back it booted up fine. What the hell could have happened? im afraid to reboot.........

It is doing it off and on now, even after I reformatted. One thing I noticed is in the BIOS the FSB gets set to 200MHz, and I always have to change it back to 166MHz before it starts working again. Is there any explanation to this? I would really like to fix it since I like to reboot often.....