select Start, then Run, type in the word MSCONFIG
when the System configuration Utility screen appears,
select the services tab, you will then see a long list of services uncheck the alerter tab(you will see microsoft beside it as the manufacturer)then select apply and close you will then be prompted to reboot.
this same screen is also useful to disable programs at start up, select the start up tab and repeat prior procedures deselect which program you would like disabled at start up, then apply and close

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