Deleting "Preview"

How do I set my OS X system to default to opening Photoshop instead of Preview each time I open a file so I don't always have to go to "open with". Does anyone recommend deleting Preview altogether? Or would this be bad. I hate it.

also...How come when I view an image in Photoshop at "print size" it doesn't measure out anywhere close to the actual measurement in inches that the image is built to be? Does this have to do with my screen format?

One more...is there a good online tutorial for mac:word somewhere. I'm finding my way around it fairly well but some of it still feels like magic to me and I can't figure a few basic things out...like where do I get my scroll bars back if they dissapear? And where is my tool palette? BaH!

I know this stuff is basic but in the amount of time it takes me to ask and perhaps get a brief response I would still be digging in books and search engines.

Thanks!

Ctrl Click on the file you want to open in Photoshop go to Open With and then go to Other...

Click photoshop and tell it to always open with

Not sure about the print size issue

Just take a look to see if there is a Word Tutorial for those questions (Tool Pallete is the little Tool Box button)