As service time goes, Windows system will naturally became very slow. Besides the viruses and hardware, generally there are still some other reasons.
Installing overmuch software
Overmuch self-starting
Overflow of junk files
Too much disk fragments
Software disaster
Damage of system file
Backward Hardware Drive
The following points are the solutions to speed up Windows.
Uninstall unwanted software.
Many people usually like to try new things and they always download special software that has some amazing functions. But after a short time they finally leave it along. So one day when you find that the operating system become slower, what you should do first is to delete the outdated software. Add /remove programs can help you.
Remove needless self-starting options.
Boot options not only slow down the booting but also take up the system RAM for a long time and finally weaken the running efficiency. As many boot options are sightless, you need to check which one is unuseful. You can type "msconfig" in run and start system configuration to check all the booting options below the label "run". But it is still difficult for those who are not familiar to computer. For some boot options can't tell their host applications which we can use other software to detect.
Clear the system.
Ordinary, there leaves some survival files when you uninstall or delete programs, which will produce a great number of disk fragment. This fragment spreads to discontinuous position on the empty sector. As a result, the moving number of the hard drive heads increases dramatically when you open the files. Finally the running efficiency of the disk becomes slow. The system's running speed can be improved by disk defragmenter.