for the past week, my mouse would periodically go crazy all the sudden. IN particular it would seem to be highlighting everything, opening, closing stuff, I was unable to defeat it in anyway, other than by turning computer off. ONce back on, the mouse would be fine.

I use a wired trackball. unplugging the track ball, which actives my laptop touchpad had no effect on the craziness.

Couple times I tried turning off the wireless connection, that did not stop the problem... but I only left it for 30-60 seconds because I was worried about security.

Finally, I decided to get a new IP number (turned DSL modem off overnight). confirmed I got new IP number and voile... a day and a half with no mouse problems.

I feel it was some sort of attack, probably trying to get passwords?

I have windows XP, my antivirus is ESET NOD, I do have security on my wireless router.

I wanted to post this becuase I've seen similar mouse issues reported, but never this solution.

Is there anything else I should check to see if there is some sort of program on my computer that was activated?

Any other steps I should take?

Have you try other anti virus software like Avira, AVG or Adware? If not give it a go and see what happen. Another way is uninstall and install back the trackball and touch pad drivers again.