how do you make sure that your computer is running smooth?

Question

like checking the computer for errors and how do you do a diagnostics check for hardware and software problems?

Answer 1

Here are some suggestions:
1) Uninstall programs you don't need or use by going to Start, Settings, Control Panel, and then Add or Remove Programs. Select the ones you are absolutely sure you don't need or use and then select Remove.
2) Run "Disk Cleanup" from Start, Programs, Accessories, System Tools.
3) Run "Disk Defragmenter" from Start, Programs, Accessories, System Tools...

If you want to do more:
Download and use CCleaner from here (Free), which can do a good and safe job with cleaning your registry, etc.:
http://www.ccleaner.com/

Also get and use a good spyware detector/cleaner program, such as Spybot Search and Destroy from here (Free):
http://www.spybot.info/en/index.html

Also, make sure you have a good and frequently updated virus protection software...

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That's a good, safe start...