Star Office will install and run properly on a Windows system.
I don't believe that all versions of MS Office can open documents saved as native Star Office documents. You can open and save documents and spreadsheets in MS Office format on Star Office.
I recommend that you go to www.openoffice.org and download the latest version of Open Office. That way, you can evaluate the package at no cost.
Open Office is the same basic software as Star Office. It is just a little older version and has only user forums for support.
If you like Open Office, and would prefer full support, you can go ahead and buy Star Office.
I install Open Office on most of the systems that I build for home users.
Chas