Could it be that you've accidentally turned on Sticky Keys?
Here's an explanation:
To turn on StickyKeys
StickyKeys is designed for people who have difficulty holding down two or more keys simultaneously. When a shortcut requires a key combination, such as CTRL+P, StickyKeys will enable you to press a modifier key (CTRL, ALT, or SHIFT), or the Windows logo key (), and have it remain active until another key is pressed.
Open Accessibility Options.
On the Keyboard tab, under StickyKeys, select the Use StickyKeys check box.
To turn off StickyKeys, clear the Use StickyKeys check box.
Notes
To open Accessibility Options, click Start, point to Settings, click Control Panel, and then double-click Accessibility Options.
If the Use shortcut check box in the Settings for StickyKeys dialog box is selected, you can turn StickyKeys on or off by pressing the SHIFT key five times.
For more information on changing StickyKeys options, click Related Topics.
Related Topics
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