There are many applications for defragmenting, but i would trust Microsoft to know their own software on this.
Competition and familiarity are wonderful things. Many companies have word processors. From notepad, wordpad, MS Works, Word Perfect, Word, Office Word, and the list goes on... in fact i believe all of those were microsoft products, but there are apps such as VI or emacs for *nix.
The Windows Live Writer I have not used yet, but from what i've read the key benefits are live hosting, allowing web developers to use SDKs instead of just standard work processing tools to modify code as well and host files. I cannot actually say how easy they make this, but i'll stick to my FTP and SCP for now :P
Absolutely, ( you may need to insert your windows disc) under add/remove applications in control panel, choose the windows compenents and go through and find the applications you want to remove and uncheck the boxes. Click apply and the programs are gone.
If you are using Vista i believe the terminology is a little different if you need more help, post and i'll use my VM to find the exact solution