Euro-symbol displays wrong since reinstalling Office

I just had to install a new harddisk and reinstall everything.  Installation went OK, but I notice that since then Excel frequently (but not always) displays a vertical bar instead of the Euro-symbol (€). This is MS Office 2007, which I gather is no longer supported, but I don't need a software fix, I just want to know why it is doing this (it never did before).  Or if there is something I can do to make it display correctly.

Usually the Euro symbol displays correctly for formula fields, but not for a simple amount.