Microsoft Windows

System Boot Sequence

The system

BIOS is what starts the computer running when you turn it on. The following are the steps that a typical boot sequence involves. Of course this will vary by the manufacturer of your hardware, BIOS, etc., and especially by what peripherals you have in the PC. Here is what generally happens when you turn on your system power:

1. The internal power supply turns on and initializes. The power supply takes some time until it can generate reliable power for the rest of the computer, and having it turn on prematurely could potentially lead to damage. Therefore, the chipset will generate a reset signal to the processor (the same as if you held the reset button down for a while on your case) until it receives the Power Good signal from the power supply.
2. When the reset button is released, the processor will be ready to start executing. When the processor first starts up, it is suffering from amnesia; there is nothing at all in the memory to execute. Of course processor makers know this will happen, so they pre-program the processor to always look at the same place in the system BIOS ROM for the start of the BIOS boot program. This is normally location FFFF0h, right at the end of the system memory. They put it there so that the size of the ROM can be changed without creating compatibility problems. Since there are only 16 bytes left from there to the end of conventional memory, this location just contains a "jump" instruction telling the processor where to go to find the real BIOS startup program.
3. The BIOS performs the power-on self test (POST). If there are any fatal errors, the boot process stops. POST beep codes can be found in this area of the Troubleshooting Expert.
4. The BIOS looks for the video card. In particular, it looks for the video card's built in BIOS program and runs it. This BIOS is normally found at location C000h in memory. The system BIOS executes the video card BIOS, which initializes the video card. Most modern cards will display information on the screen about the video card. (This is why on a modern PC you usually see something on the screen about the video card before you see the messages from the system BIOS itself).
5. The BIOS then looks for other devices' ROMs to see if any of them have BIOSes. Normally, the IDE/ATA hard disk BIOS will be found at C8000h and executed. If any other device BIOSes are found, they are executed as well.
6. The BIOS displays its startup screen.
7. The BIOS does more tests on the system, including the memory count-up test which you see on the screen. The BIOS will generally display a text error message on the screen if it encounters an error at this point; these error messages and their explanations can be found in this part of the Troubleshooting Expert.
8. The BIOS performs a "system inventory" of sorts, doing more tests to determine what sort of hardware is in the system. Modern BIOSes have many automatic settings and will determine memory timing (for example) based on what kind of memory it finds. Many BIOSes can also dynamically set hard drive parameters and access modes, and will determine these at roughly this time. Some will display a message on the screen for each drive they detect and configure this way. The BIOS will also now search for and label logical devices (COM and LPT ports).
9. If the BIOS supports the Plug and Play standard, it will detect and configure Plug and Play devices at this time and display a message on the screen for each one it finds. See here for more details on how PnP detects devices and assigns resources.
10. The BIOS will display a summary screen about your system's configuration. Checking this page of data can be helpful in diagnosing setup problems, although it can be hard to see because sometimes it flashes on the screen very quickly before scrolling off the top.
11. The BIOS begins the search for a drive to boot from. Most modern BIOSes contain a setting that controls if the system should first try to boot from the floppy disk (A:) or first try the hard disk (C:). Some BIOSes will even let you boot from your CD-ROM drive or other devices, depending on the boot sequence BIOS setting.
12. Having identified its target boot drive, the BIOS looks for boot information to start the operating system boot process. If it is searching a hard disk, it looks for a master boot record at cylinder 0, head 0, sector 1 (the first sector on the disk); if it is searching a floppy disk, it looks at the same address on the floppy disk for a volume boot sector.
13. If it finds what it is looking for, the BIOS starts the process of booting the operating system, using the information in the boot sector. At this point, the code in the boot sector takes over from the BIOS. The DOS boot process is described in detail here. If the first device that the system tries (floppy, hard disk, etc.) is not found, the BIOS will then try the next device in the boot sequence, and continue until it finds a bootable device.
14. If no boot device at all can be found, the system will normally display an error message and then freeze up the system. What the error message is depends entirely on the BIOS, and can be anything from the rather clear "No boot device available" to the very cryptic "NO ROM BASIC - SYSTEM HALTED". This will also happen if you have a bootable hard disk partition but forget to set it active.

This process is called a "cold boot" (since the machine was off, or cold, when it started). A "warm boot" is the same thing except it occurs when the machine is rebooted using {Ctrl}+{Alt}+{Delete} or similar. In this case the POST is skipped and the boot process continues roughly at step 8 above.

1. Command Name - the command to be carried out
2. Parameter - object the command should act on
3. Switch - modifies the way you carry out a command represented by a forward slash (/) and a character e.g. /F

Example.:

C:\book>Tree /F

The serial is either on the back of a CD case for the software, or it will be in the documentation. Microsoft may also place it on a certificate of authenticity for Windows. You will know it is the key because it will be a mix of letters and/or numbers separated by dashes, usually about 25 characters long. You must have the key in order to install the software. You must install the software in order to use it. Therefore you can't install or use the software without this key. Installation will have a series of on screen instructions for you to follow. One of the boxes will request the key and have white boxes for you to type the key into. Type it in and click next or continue - whichever the button says - and the installation will continue.

The activation code is given to you when you first launch the software after installation. You will only have to enter this once. You have the option of using Internet activation - which is the quickest and easiest - phone or mail activation. If you choose to do it by phone, choose the country you live in then it will give you a phone number to call. Call the number and give them your serial number and the activation number - both of which will be listed on the screen where you can easily see it. They will then give you the activation code that you will need to enter into the white boxes. Whichever you choose - Internet, phone, or mail - just follow the onscreen instructions to get the code. Contact Microsoft customer support to obtain a new key if you have misplaced yours. They will probably need some sort of verification, such as original receipt or bar code on the box or even the certificate of authenticity number. Of course, they will instruct you on how to obtain a new key and what is needed by you. Downloading the software without purchasing (retail versions) is illegal and it is called piracy. It is also illegal to use a key that you did not purchase because in this case you did not have to purchase the software either. Even if you have purchased the software and you use the Internet to find a key and use it - it is illegal - because if you really did purchase the software, Microsoft will help you obtain a new one. It is also illegal to use key generators (keygens), cracks, and no-CD cracks.

Note: This is a catch-all question. Neither it nor its alternatives should be deleted. It should also remain protected.
Every legitimate copy of the software has its own UNIQUE product key. If you have copied the software - you are committing piracy and the law-abiding members of the Wiki community will not help you.