Grammar #3

What is the difference between affect and effect? I don't have any idea how to differentiate between the two! According to the website Writers Block (http://www.writersblock.ca/tips/monthtip/tipsep99a.htm) here's the difference:

Affect Vs. Effect

Affect and effect are two words that are commonly confused.

"Affect" is usually a verb meaning "to influence".

The drug did not affect the disease.

"Effect" is usually a noun meaning "result".

The drug has many adverse side effects.

"Effect" can also be used as a verb meaning "to bring about".

The present government effected many positive changes.