Searching for multiple words in a cell

Here it is...

I've never used macros before so please excuse my complete igorance of the subject! I'm wondering if it's possible to have the program identify exact matches of the keyword (such as capitalization)? Also, I noticed when I repeat this process with an extremely large file, say 3000 rows of text, the macro debugger pops out - is there a size limitation to the operation of this macro?

Thank you so so much!