asookermany :
I installed microsoft security essentials and after updating mse my computer windows xp freezed and only turned off by cutting the power. It continued to freeze or turn off.
What Antivirus do you use ?
Did the MSE install run without error ? It did not conflict with Antivirus
you run ?
What do you mean by : "After updating MSE" ?
You might want to uninstall / reinstall MSE, with AV temporarily disabled.
That is: download MSE, disconnect from Internet, disable AV, Install MSE, enable AV.
There are also settings to exclude the apps from interfering with one another.