Windows 7: Left click sometimes does strange things

My laptop keyboard and mouse keys are starting to wear out, but one problem seems particularly curious. The left click on my touchpad mostly works normally, except in a few situations. In Chrome (but not IE), when I click on a tab, the tab closes. I'm not clicking the X or anywhere near it. Also, when I click on Chrome's back button, the previous page opens in a new tab, rather than it sending me back within the same tab. And it's not just Chrome. Sometimes when I click on a program window, Windows "unfocuses" that window, so the window title bar turns a lighter shade, like I've clicked on something outside the window.

I'm wondering if Windows thinks I'm holding down a key when I'm clicking my mouse? I've tried to find info about Chrome that would suggest what would make a left click behave this way, but I'm stumped.

Does everything run fine with the touchpad?
If so its your mouse.
You either need new batteries or a new mouse.
Or you'd need a wired mouse.
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Also try a different browser like Mozilla Firefox.
Is their a difference?
Run a system scan with AVG anti virus.

Download and Run CCleaner.

Hope this helps

Sorry, I'm not using a mouse. "Clicking my touchpad" just sounded weird to me. It's when I click the left button on my touchpad.

I've actually just replaced the hard drive, and I have the same problem as with the previous hard drive, and a system scan found no threats. So it's not the software.

I get the "unfocus when clicked" problem in lots of different applications, so it's a system-wide thing. But there are peculiarities in different programs.

Also, this problem comes and goes.