Only Allow PasteSpecial as Text/Values in specific sheets

I have a workbook with 3 sheets. Sheet_1 has user inputs that are referenced in Sheet_2.
Example:
User puts "1RW9770STA123456" in cell S19 of Sheet_1
Cell C19 in Sheet_2 will have this formula: ='Sheet_1'!S19

The user copies the "1RW9770STA123456" from another application then pastes it into Sheet_1 Cell S19 - which frequently causes the formula in Sheet_2 Cell C19 to change to: ='Sheet_1'!#REF!
Is there any way to disable all Paste and PasteSpecial options except the PasteSpecial As Values/Text in Sheet_1 only? The code would also need to disable the moving of cells or dragging of cells in Sheet_1.

The workbook was created in Excel 2010, but people with Excel 2007 and Excel 2010 will use the workbook.

I hope this makes sense.
I appreciate any help on this.

That works quite well! Two things I've noticed:
1. The cut/copy/paste is still enabled in the Quick Access Toolbar.
2. Any chance this code can be modified to apply to just Sheet_1 and Sheet_2?

Thank-you very much!

That works great! Thank-you very much!