1. Overmuch icons on desktop lead to long Windows 7 startup time
Having excessive icons is one of the main causes of Windows 7 decelerated boot-up. To get the problem fixed, delete shortcut icons that are not being used frequently or create a folder to store them. For example, you can create a home folder and multiple sub-folders which can be used to store icons that belong to different categories such as game, work, etc.
2. Uninstall software or hardware that slow down Windows 7 startup
If Windows 7 begins to boot up slow recently, it is most likely caused by software or hardware conflicts which extend the boot-up time of Windows 7. To uninstall software and hardware that are newly installed would easily fix windows 7 slow boot.
3. Cut out external hardware that makes Windows 7 slow startup
To improve Windows 7 sluggish startup time, the less external hardware the better, because Windows 7 scans for external hardware and has to load up their drivers on its startup every time.
"Floppy drive seek at boot up" that is still activated by default in some most recent motherboards renders Windows 7 decelerated startup, due to this it should be turned off since floppy drive had withdrawn from the market.
4. Maintain registry to keep Windows 7 slow startup from occurring
Windows 7 startup inevitably slows down, when the registry is not maintained carefully. If Windows 7 is compared to a kitchen, then the registry can be compared to a cook. Over time the cook will get dirty, tired and can not work productively if not given enough time to recuperate. However, the registry can't recuperate automatically unless there is an outside force that helps to maintain it
you may use some secured program such as McAfee secured reginout to fix registry related issues.