If you have an older computer that tests the memory every time you start and go through several start-up screens are a way to remove it. Restart your computer and enter bios. Look for boot options and enable quick boot. This will allow you to skip all the unnecessary start screens and other sequences.
Not all PCs have this option. Next you will want to look at your antivirus program. Going to the Options menu, and make sure it does not scan every time you start your computer. If disabling this setting may actually slow down your boot time.
You'll also want to do a general cleanup on your hard disk. You can do this, select your hard drive and run Disk Cleanup. You can also remove any old programs you no longer use, the less software your PC has to load, the faster it will be. Next, you want to remove any programs start, you do not quite need. The problem is Windows XP made this difficult. There is really no easy way to do it. You may download a third party program like tweak UI. Or most registry repair will enable you to eliminate start-programs safely.
Next you will want to do a full virus scan and also a scan for spyware and ad aware. If you have not performed maintenance on your computer for a while you may be shocked at what it finds. All the above suggestions may help, but in most cases, the biggest problem for slow boot is a corrupted or damaged registry. You need a good registry repair program to fix it.
The computer records contain all the files and settings that your software must reference every time it loads. Over time, from uninstalling and installing software registry gathers a lot of orphaned files. These should be cleaned or repaired. Wrong closures, viruses, crashes, improper uninstalls, or spyware will cause your registry to become corrupt or bloated over time.
When you start your computer startup sequence refers to the registry to load the software. It may be looking at a corrupted files and software that no longer work or on your computer. In most cases the reason that Windows XP boots so slow. You should perform regular maintenance on your registry to keep it fully optimized. Doing so is like giving your computer or a set. You will be surprised at the increased performance and speed up your computer.