Problems emailing groups

Unable to reliably email to groups.

I am using Windows 8.1 on a new HP computer.

Two problems appear to occur:

1. After plugging in group name and click send, a message comes up asking for an email address. If I place an extra address in mail only goers to that address;
2. When a group email does go out it only goes to one or sometimes up to a 1/3 of the group