Hi there! It sounds like you're having a couple of issues with your Excel workbook. Let's tackle them one by one.

Firstly, if the merge cells button isn't working, it's possible that the cells you're trying to merge are either already merged or contain data that can't be merged. Here's what you can try:

1. Select the cells you want to merge.
2. Go to the "Home" tab in the ribbon.
3. Click on the "Merge & Center" button in the "Alignment" section.
4. If the button is grayed out, try unmerging any cells that are already merged in the same area. You can do this by selecting the merged cells and clicking the "Merge & Center" button again to unmerge them.
5. If there is data in any of the cells you're trying to merge, try clearing the contents of those cells first by selecting them and pressing the "Delete" key on your keyboard.

If none of these steps work, it's possible that the workbook has some kind of protection or restriction in place that is preventing you from merging cells. In that case, you may need to contact the person who created the workbook to find out what's going on.

As for the "delete sheet" option being deactivated, it's possible that the workbook is also protected in some way. Here's what you can try:

1. Right-click on the sheet tab at the bottom of the Excel window.
2. If the "Delete" option is grayed out, try unprotecting the sheet by going to the "Review" tab in the ribbon and clicking on "Unprotect Sheet" (if this option is also grayed out, the workbook may be protected at the workbook level, in which case you'll need to contact the workbook creator).
3. Once the sheet is unprotected, try right-clicking on the sheet tab again and see if the "Delete" option is now available.