Mouse trouble

I have a fairly new home-built computer that's having mouse related trouble. My mouse looses the ability to move my cursor vertically with annoying frequency. I don't think that the mouse itself has trouble, although it could be related to mouse configuration. I can force the problem to occur at any time by clicking on the "Edit" menu button in Konqueror. After that I can't do anything with the computer other than power it off, and move the mouse cursor left and right. Ctrl-Alt-Del doesn't work, nor does Ctrl-Alt-Bkspc, nor Ctrl-Alt-Fn, nor do the kernel SysRq keys.

I've googled a lot, read FAQs, and haven't be successful at all in changing the behavior.

My system uses an Athlon 4200+ 64-X2 in an ABIT AV8-3rd Eye motherboard. The video card is a Radeon 9250. The keyboard is Logitec, and the mouse is a 3-button Logitec unit which I've used quite a bit with a laptop and with no problems in that application.

The OS is Mandriva 2006.0.

Can anyone please advise me on this?

Thanks....

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