"ntoskrnl.exe is missing or corrupt"appears unless disk is inserted

When I installed Windows 7 Pro x64 today, I did a custom install but I didn't format my drive beforehand. After it restarted the first time, it came up to a screen that said this:

Code:

Windows could not start because the following file is missing
or corrupt:
< Windows root>\system32\ntoskrnl.exe.
Please re-install a copy of the above file

After several failed attempts my Dad somhow got it to install properly, and it worked fine until I needed to reinstall updates. When it restarted again, the same screen came up. I put in the Windows 7 DVD and restarted, this time it booted without any problems. My boot is setup as "Boot from CD/DVD Drive" first, and "Boot from HDD" second. But when it said "Press any key to boot CD/DVD" I didn't press anything, and it just moved on normally.
I ran the startup repair but it did not find any problems.
So can somone tell me how to fix this?
Thanks

Is it the problem now?

bomberswarm2 said:

My boot is setup as "Boot from CD/DVD Drive" first, and "Boot from HDD" second. But when it said "Press any key to boot CD/DVD" I didn't press anything, and it just moved on normally.
I ran the startup repair but it did not find any problems.
So can somone tell me how to fix this?
Thanks

It is not anything abnormal. If the Optical Disc Drive is set to be the first boot device, then every startup will try to boot from it. If there is no bootable disc in that ODD, it will not show the "Press any key to boot CD/DVD" notification, and will automatically search for the second boot device, which is the HDD.

Remove the windows disc from the ODD tray, and try startup your computer. Let us know the results. Is it still saying ntoskrnl.exe is missing there?

Also, let us know the source of the windows disc. It may be a corrupted one itself.

Arc said:

Remove the windows disc from the ODD tray, and try startup your computer. Let us know the results. Is it still saying ntoskrnl.exe is missing there?

Also, let us know the source of the windows disc. It may be a corrupted one itself.

I'm not sure if it is fixed yet, but I removed the disc and told it to boot from the HDD, selected one and it started. I tried again, and it also worked. I'll change the boot device soon, so I think it will work.

I guess there is no more of a problem, seeing what you stated :)