My cousin turned her laptop on the other day to find that it reported a non-system disk error. It instructed to remove the non system disk and strike any key to continue.
Now this error usually comes about when the BIOS can't find the boot sector files for the Operating System. Considering she is massively unlikely to have messed with the boot order in the BIOS and that there are no non-system disks in the computer, could the hard drive or BIOS be corrupt?
I would then recommend you go into the BIOS and perform the HD Test that it probably has.
If it does not have that, then I would recommend you get a utility off the internet that will perform that for you.
If it pass the test, then you could be dealing with a systemboard / drive controller issue. You can truly test this by putting another drive in there that has an OS and see if it will start booting (though I would not recommend you let it boot all the way).
If it does boot and the drive pass all test then it could simply be the boot and windows system is hosed up. You could try to do a fixmbr on it to resolve that.
If all else fails you may need to try to extract the data off of the drive by connecting it through USB to another machine and then just format and reload the drive.