What happens when a mouse starts to fail?

I'm curious, because suddenly I've been experiencing erratic mouse behavior...I'll be scrolling down a webpage using the scrollbar and the pointer will suddenly jump to the center or far left of the page; sometimes as I move the pointer across a page a right-click menu will pop up, or random text will be highlighted, or even more aggrivating, the browser window will close.

I'm sure this isn't a security/hacker issue. I'm on dial-up, there's never any data-transfer activity going on at the time this happens (not sure if that applies), and it's all very erratic and random-type behavior. It's not like someone is manipulating things behind the curtain.

I use the original two-button mouse that came with the 3 year-old Compaq machine. Does this sound like simple mouse failure?

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