Search and highlight hits only in Column C

The person in charge of this project just changed the requirements. (Ugh!) Now it has to work like this:

1. The user enters a keystroke (perhaps ctrl+alt+s) to bring up an input box.
2. The user enters a word or phrase into the input box and submits it.
3. Excel does a non-case-sensitive search in column C for the word or phrase. (Words and phrases in column C are separated with commas.)
4. For every occurrence of the word or phrase in column C, excel highlights in yellow the cells in columns A, B, and C of that row.

For example, in the attached workbook if the user searches the "Medical" worksheet for "MED5" and "med5" is found in C2 and C4, then cells A2:C2 and A4:C4 would be highlighted in yellow.

This will obviously require a custom macro and I'm not a VBA programmer. Does anyone have a similar macro?