You're working, surfing the internet or writing an email and your computer locks up. One of the first things you should try in attempting to recover from a lockup is ending the application which has caused the freeze. You can do this by using a native program called Task Manager. If you press CTRL+ALT+DEL, that is press Control, Alt and Delete at the same time, Task Manager should open. In this little window you can view a list of running applications.
Assuming Task Manager will open, check the list of applications for any programs that say "not responding" under Status. If Internet Explorer or any other applications you had open read "Not Responding", then you may Right-Click on them and select "End Task" from the menu. This should close the running application, if you are prompted to "End Now" or "Wait for it to respond" choose to "End Now". By doing this you may lose any work you had open in this application but it will normally allow you to save anything else that was open at the time of the freeze.
If Task Manager is not working for you and you have no other way of closing the frozen computer programs then you may try powering down the computer. The easiest way to do this when the computer is not responding is by holding the power button in for about ten to fifteen seconds. The machine will power down, if it does not your last resort is to physically unplug the computer from the wall. Once powered down you may turn it back on and resume working, hopefully problem free.
NOTE: By powering down the computer when it is locked up you will almost certainly lose any unsaved work. This should always be a last resort.
If you continue having problems with the laptop or computer you may want to call a computer repair technician.