mouse clicking issue?

[Halder]

I have both Firefox and Internet Explorer, which I both use depending on the dependability/security of the site I am visiting. The issue is that, often I will have 4 or 5 Firefox windows open and when I close one, they all close, or 2 or 3 close of the 5. I thought that this was an issue with Firefox but when I have several IE windows open and I close one, two, three or all close at the same time as well.

Similarly, when I am on a website and I access a link to another site, 2 or 3 Browser windows open to the same link (regardless of the link).

This issue is also evident when opening any other window, such as "My Computer" (as the window will open twice) and such, but it is much more prominent in opening/closing the Browsers.

I thought it might have been a mouse sensitivity issue and have tweaked that but either I have not done it right or it isn't the mouse.

Ironically, I have no such issues (mouse clicking, accessing windows) at all when playing any game.

BTW, I am running an up to date version of XP.

Thanks in advance for any help or advice you can offer.
Halder