Safari Missing On Windows Laptop

Ok so here is the thing. My mums friend had a windows computer and i fixed it up by installing safari and then a few addons that will speed it up. She just called today and gave me the message that safari has gone. Now she is the only one who uses the computer and she dose not remove any programs. So i would like to know why this has happened. Please help as soon as possible as she would like to know what has happened so that it can be fixed or noted.

Thanks

matt1100