Computer goes too slow

The obvious first question, do you have well-maintained anti-virus/malware software? If not, this is the first thing I would do.

Other then that, for anyone to help you will need to provide more information.

How old is the computer? What OS is it running? What is the processor? How much RAM? What kind of Internet do you have (dialup, cable, DSL)?

first delete your temporary files,for this go to start menu then click run ,then write there "temp",then you will see the files.You can also re install the OS,then your PC would be faster.

Malware and not performing routine maintenance can often account for slow computer operations. In addition to the suggestions already made, you can use the Disk Cleanup Utility in Windows to get rid of unnecessary crud (forgive the technical term), take the time to delete old or unused files (or save them to disk and then delete), and then defragment your hard drive.

mmm...interesting, thanks for info

I probably need more RAM.

Something to check is the number of applications that load on startup. Many applications, to make launching them quicker, will partially load just in case you might need it (media players are notorious for this). Some will load an update finder when you boot.