Case Dependancy Trouble With InStr() And Mid()

I'm having some trouble with an error that is thrown when I use InStr() and Mid() with a database search query. In point form:

I am retrieving an array strings from my database where the query is case insensitive. This is good.

Then I locate the keyword in the string using InStr() which is case sensitive. This is not desireable as it doesn't recognize all instances of the keyword.

I use the Mid() function to give me a portion of the string starting at the location provided by InStr() which is sometimes the number zero which in turn throws the error.