MS-Windows Keyboard Shortcuts

As compiled by me, over the years.

Window Control

Alt-Space
Open the current app-window's "control menu" (AKA "system menu")
(The thing you get by hitting the "-" to the left of the app's title bar.)
Alt-"-"
Open the current document-window's "control menu" (AKA "system menu")
Alt (by itself)
Select the first (normally, leftmost) item on the Menu Bar. (Maybe "File", maybe the document-window's control "-" menu)
F10
When not overridden, same as Alt (by itself).
Shift-F10
Win9x: When not overridden, pop up the "shortcut menu" (same as right-mouse-click -- often called "Properties")

Application & Document Switching

Ctrl-Esc
Pop up the Task List window.
Win9x: Pop up the "Start" menu.
Alt-Esc
Switch to the next application
("Next" referring to the next one down in the order of apps you get when you hit Ctrl-Esc.)
The current (topmost) app goes to the bottom in the new order. (Note that minimizing an application also sends to to the bottom of that tasklist order.)
Shift-Alt-Esc
Switch to the previous applicaton.
("Previous" referring to the farthest one down in the order of apps you get when you hit Ctrl-Esc.)
The current (topmost) app goes to second place in the new order.
Alt-Tab
Switch to another app.
(Hold Alt and repeatedly press Tab in order to go thru the apps listed in the order they're listed in in the Ctrl-Esc list. I.e., you start from the 2nd-from-the-top and move down.) The current (topmost) app goes to second place in the new order.
Shift-Alt-Tab
Switch to another app.
(Hold Alt and repeatedly press Tab in order to go thru the apps listed in the order INVERSE to how they're listed in in the Ctrl-Esc list -- i.e., you start from the bottom and move up.) The current (topmost) app goes to second place in the new order. You can shift from Shift-Alt-Tab order to Alt-Tab order as long as you hold down Alt.
Alt-F4
Close this app.
Ctrl-F6
Switch to the next document window in this app.
Shift-Ctrl-F6
Switch to the previous document window in this app.
Sometimes unrecognized, or assigned another function.
Ctrl-Tab
Same as Ctrl-F6.
Sometimes unrecognized, or assigned another function.
Shift-Ctrl-Tab
Same as Shift-Ctrl-F6.
Sometimes unrecognized, or assigned another function.

Form-Box Screen Control

Tab
Move to the next field (radio button group, picklist, scroll-list, checkbox, button, etc).
Shift-Tab
Move to the previous field.
Space
Toggle the state of checkboxes.
Up or Left
Generally: Switch to (and make active) the previous radio button in this field.
Or, in a picklist, switch to the previous option in this picklist.
Down or Right
Generally: Switch to (and make active) the next radio button in this field.
Or, in a picklist, switch to the next option in this picklist.
Ctrl-Home
Switch to the topmost option in this picklist.
Ctrl-End
Switch to the bottommost option in this picklist.
Alt-Up or Alt-Down
Expand or Contract the drop-down for the current picklist. (I.e., toggle between just the one line, or a few lines with a scrollbar.)

Screen Capture

PrintScreen
Snapshot the screen to the clipboard.
Alt-PrintScreen
Snapshot the current application window to the clipboard.
(Note that there seems to be no corresponding keystroke for getting just the current document window.)

Clipboard

Ctrl-Ins
Copy
Shift-Ins
Paste
Shift-Del
Cut

Cursoring

Shift- with any of the below means "continue (or start) selecting, while moving the cursor to..."
Home
Start of current line.
End
End of current line.
Ctrl-Right
Start of the previous word.
Ctrl-Left
Start of the next word.
Ctrl-Home
Start of doc.
Ctrl-End
End of doc.
Ctrl-PgUp
Top of the current window.
Ctrl-PgDn
Bottom of the current window.
PgUp
Scroll the current window one screen-worth up.
PgDn
Scroll the current window one screen-worth down.