How to Fix Windows Startup Problems

There are many reasons why Windows may not be starting. Sometimes it may be related to hardware, while other times it may be due to malware (particularly rootkits). When you start your computer, you may receive one of the following error messages: Missing operating system or operating system not found Error loading operating system Invalid partition table Bootmgr is missing Windows failed to start Stop 0x0000007b Windows blue screen (BSOD) Or you may see Windows black screen with no error message. This guide provides step-by-step instructions on how to fix Windows startup problems. Please note that the instructions below are for Windows 7 and Vista users. If you are using Windows XP, follow the instructions on this page. Contents  Step 1 – Start Windows Recovery Environment   Step 2 – Use Startup Repair to Fix System Files  Step 3 – Fix Windows Master Boot Record  Get Expert Analysis Note: Before following the steps below, try starting the computer in Windows Safe Mode with Networking. If you can start in safe mode, follow the steps in this malware removal guide. Step 1 – Start Windows Recovery Environment  Start your computer and press and hold the F8 key while your computer starts up. You will see a black screen with a number of options. Select the Repair Your Computer option, and then press the enter key. Choose your language, and then click Next.  Note: If the Repair Your Computer isn’t listed as an option or doesn’t work, you will need to create a system repair disk. Step 2 – Use Startup Repair to Fix System Files On the System Recovery Options menu, click Startup Repair. It will scan for missing or corrupted system files and fix them. Your computer might restart several times during this process. If Windows won't start after using Startup Repair, move on to Step 3. Step 3 – Fix Windows Master Boot Record The master boot record, also known as MBR, contains code that is necessary to start Windows boot process. Certain types of malware, such as bootkits, will infect and corrupt the MBR, which can prevent Windows from starting. Follow these instructions to fix the MBR: On the System Recovery Options menu, click Command Prompt. Type bootrec /fixmbr and then press enter. Note: There's a space between bootrec and /fixmbr. Now, restart your computer. If that doesn’t work, start back into the system recovery, and type bootrec /fixboot and then press enter. Then type bootrec /rebuildbcd and then press enter. Now, restart your computer. Note: If you get an "element not found" error with any of the commands, you need to mark your OS partition as active. Follow these instructions to mark a partition as active: Open Command Prompt and type diskpart, and then press enter. Type list disk, and then press enter. This will list all disks attached to your computer and assign them a disk number. Type select disk (followed by the number of the OS disk; most likely 0), and then press enter. Type list partition and then press enter. You will now see a list of partitions on the selected disk. Typeselect partition (followed by the number of the OS partition; most likely the largest partition), and then press enter. Typeactive, and then press enter. Now, try the commands again. Example What do these commands do? bootrec /fixmbr - fixes the MBR of the system partition. bootrec /fixboot - writes a new Windows boot sector onto the system partition. bootrec /rebuildbcd - rebuilds the boot configuration. Get Expert Analysis If Windows won't start after following all of the above steps, I recommend that you create a topic at one of the forums listed below and ask for help. These forums have experts who are willing to help you. Be sure to mention in your topic that you followed this guide. Note: You will need to register for a forum account to create a topic. Free support forums: Bleeping Computer, Tech Support, Cyber Tech Help, PC Help Forum Notable Links How to Speed Up a Slow Computer What to do if Windows won't start correctly