There are some common keyboard shortcuts which work within Windows and other Microsoft products and because these are widely used other software will use the same shortcuts as well.
The most useful ones are in terms of cutting and pasting.
Highlight the text you wish to copy and then pressing CTRL+C (that means both buttons at the same time) will copy the text to the clipboard. If you press CTRL+X you will effectively be "cutting" it out from the original source ie this removes it from the original.
If you now go to the place you wish to paste the text you need to put the cursor inside the box etc by clicking in it and then pressing CTRL+V will paste the text into that box.
Formatting shortcuts which might be commonly used would be:
CTRL+B for BOLD
CTRL+I for Italics
CTRL+U for Underlining
These shortcuts toggle the status between on or off ie if something is already bold then CTRL+B will turn it into plain text and a further CTRL+B would turn it back into Bold.
Another useful one is CTRL+A - this selects all of the text in the specified area. This can be a bit of overkill though if you only need part of something. For instance pressing CTRL+A whilst posting this message would select everything. Pressing CTRL+A once the message has been posted in comms would select all of that webpage including all the MSN headings etc.
Getting used to these keyboard shortcuts can save you time and you then don't need to keep remembering which little icon is for which command.