Event viewer is a small tool that Microsoft has built into Windows to keep a running log of the things that Windows does.  Windows records these "Events" and stores the information in a log file.  They were even kind enough to sort the hardware events from the software events for us

There are many ways to open Event Viewer  I normally just click on the Start Button,  go to "Run", and type "eventvwr" in the box (without the quotes).
See "How to open Event Viewer"

You could also go START>CONTROL PANEL>

When Event Viewer opens up, you will see that the window is split into two sections.  Just like in "My Computer", you click on an item in the left pane, and the contents are displayed in the right pane. 

The two sections we are interested in are "Applications" for software, and "System" for hardware.  Click on either of these topics in the left pane, and the log file will be displayed in the right.  The list in the right is displayed from the most recent to the oldest, in the order they happened.

Double clicking on any message in the right pane will bring up a detail box with specific information about the logged message.

Event Viewer opened
Since this computer was running incredibly slowly, I decided to look in the "System" log and see if anything stood out.  Wanna make a guess as to what the problem was?
event viewer error log
Critical error icon
Warning Icon
Just an ordinary message
Something unusual happened!!
Something BAD happened!!
Information icon ion event viewer
Event Viewer will look like this when you open it
To see hardware problems, select "System" in the Right Pane.
For software problems select "Applications"
You can double click on any specific message to see details about that particular message.
error message details
You need to also keep in mind that Event Viewer will only log items that Windows monitors.  It may not see many problems, but when it encounters a serious error, it will log it.  This means that Event Viewer is a tool only, to HELP you figure out what is going on with your stupid damn computer. 
Before you do anything I suggest in this site
How to back up your computer

2008/2012 Stupid Damn Computer--all rights reserved
When you look at the right pane, you will see the messages that the system generates.  If the message is a routine message, the message will not be flagged.  If something happens out of the ordinary, you will get a yellow warning icon, and when anything critical happens, you get a red icon.   See the examples below.

Home   |   Backup Center     |     Troubleshoot your computer     |    Chuckle of the Day
Fix your PC button
Make money with your phone button
Make Money online Button
Build your own website button
Chuckle of the day button

How to use event viewer

Free computer repair help

Bitcoin Secrets
Learn now, EARN NOW!!

Free Crypto Currency!!
Bitcoins, Litecoins, Feathercoins
Free Bitcoins every 24 hours.

Lost Something?
Data Recovery Pro
Bring back those lost files!!

Computer Slow?
PC Health Advisor Pro
Update drivers, clean registry, clean malware