Dragging a mouse to select text in Microsoft Word requires the precision of a diamond cutter, or seems to, anyway. I prefer to press the Ctrl, Shift, and arrow keys to make my text selections. Throw in a couple of function keys, and I can use my keyboard to select text faster than any mouser can.
To select a word at a time, press Ctrl-Shift and the left or right arrow key. Ctrl-Shift and the up and down arrow keys select a paragraph at a time. If you get tired of holding down the Shift key, simply press F8 to put Word into select mode. The Ctrl-arrow key operations still work, but you can also select the current word, sentence, paragraph, and section by pressing F8 repeatedly. As you might guess, pressing Shift and F8 deselects in the opposite order.
The real power of Word's select mode comes from combining it with the Find and Go To functions. Suppose you want to select from the cursor to the next occurrence of the word "wolverines." Simply press F8, F5, and Alt-D to open the Find and Replace dialog's Find tab. Type in the word you want to select to and press Alt-F (or Enter if the Find Next button is selected).
If you want to select to a specific page, heading, footnote, or other element, press Alt-G to highlight the Go To tab, select the element in the "Go to what" drop-down menu, enter the appropriate option in the text box to the right, and press Alt-T (or Enter if the Go To button is highlighted).
To exit select mode, just press the Esc key. It will also close when you cut, copy, or format the selection.
Here are a couple more helpful key combinations for selecting in Word:
Shift-Home/End selects to the beginning/end of the current line.
Ctrl-Shift-Home/End selects to the beginning/end of the document.
Shift-Page Up/Down selects one screen up or down.
Alt-Ctrl-Shift-Page Down selects to the end of the current window.
Ctrl-Shift-F8 and the arrow keys selects a rectangular block of text.