Booting problem in Lenovo ThinkPad T400 laptop

I wanted to upgrade my operating system on Lenovo ThinkPad T400. For upgrading I have successfully installed Microsoft XP operating system on it. After successful installation of windows operating system there is a problem with my Lenovo ThinkPad T400. When I start the system it won’t boot. I also tried to remove the hard disk and connect it into the USB port of the system. After connecting hard disk into the USB port I restarted the system. I am facing the same problem of booting. I want a solution to troubleshoot booting problem.

If your windows XP operating system is not booting then you can use the system restore tool. System restore runs in the background and monitors the critical functions of the components. When it finds any type of malfunction it creates a restore point immediately. You can use the system restore by pressing the Ctrl+ Alt+ Delete keys. A message will appear and select your operating system to start. Press F8 key to go into the advanced options menu. Select safe mode by pressing enter key. After selecting safe mode it will start booting. Now go to Start/ All Programs/Accessories/System Tools and select System Restore. You need to open the System Restore wizard and select restore my computer to an earlier time. Click on next button to proceed further and the restoration will start. Now your system will start booting.

You can use the recovery console to start booting of your system. For using the recovery console you will require a windows XP bootable CD. You need to insert the CD into the CD-ROM drive and press Ctrl+ Alt+ Delete keys to reboot the computer. After rebooting the system it will boot from the CD and follow the prompt for loading the basic files that are needed to run the setup. When you see the s=welcome screen press R to start the recovery console. Now it will display a folder containing the operating system files and prompts you to choose the operating system you want to log on to. Now you need to press the menu number on the keyboard and you need to enter the Administrator's password. After providing password system will booting.

There is a small part on the hard disk which is known as partition sector. In this partition boot sector information about operating system files and machine language program which is used for assisting the operating system as it loads. If your operating system is not booting then there might be a possibility that partition boot sector has been corrupted. To solve partition boot sector corruption problem you can use a special tool called as Fixboot to fix it. Start the booting by using windows XP CD and go into the recovery console. You need to type Fixboot [drive]: where drive is the name of the drive in which you want to create new partition boot sector. After creating partition boot sector restart the system and booting will be started.

If you are unable to repair the Windows XP system that is not booting then you can restore by using the recent backup that you have stored in the backup media. This method will restore the system depending upon which backup utility you are using. Taking backup from the backup device will restore your system and booting of the system will start.

As Microsoft windows XP begins to load, Ntldr program refers to the Boot.ini file which will determine where the operating system files are located and which option to enable as operating system continues to load. So if there is problem in Boot.ini file then it may cause error in booting. If your Boot.ini file is corrupted then the operating system will not boot. To repair Boot.ini file you can use a tool known as Bootcfg tool to fix it. You can use this tool after booting the system and starting the recovery console.

Windows XP might not boot because master boot record has been corrupted. The master boot record contains the partition record for every disk as well as small programs. You can fix the corrupted master boot by going to the recovery console and using the Fixmbr tool. Start the recovery console and type the below command
Fixmbr [device_name]
The device name is the new device pathname into which you want to write a new master boot record.