Hi I'm new to Mac's and a bit computer challenged, so I need someones help!

We set our new MacBook up everything was working perfectly, then I had to re-load the OS, dont ask me why, a stuff up with our internet connection. Now I have two problems, one is everytime I open Word or Power Point etc an error message comes up "an unexpected error occurred while trying to load the microsoft frame work library" once I ok this it works fine. But can anyone tell me how to fix it?

The second problem is that I now have 2 users set up on this laptop, both in th same name, I want to get rid of the original one without ruining anything.

Thanks in advance! And I am rapt I found this site there is so much info on here, it is great.