If you can get into BIOS without issues and are able to navigate using keyboard, the hardware is working.
If the computer (notebook) does not boot into Windows, then it is most likely a file system error (BCD file corruption) or a hard disk issue.
Download and run the EasyBCD software, or use a Windows Retail DVD and follow repair options that are non-destructive to user data.
I do not work for Lenovo, I only provide suggestions based on my personal willingness to help others. All advice and comments are based on my experience, and do not reflect Lenovo policy, terms or conditions.