ffimmu

I have a huge problem with my system where I boot up normally and then usually after 5mins or sometimes automatically the cursor has a mind of its own.

If Im on the desktop and highlight a shortcut it will then go through each icon upwards.
If Im on a word document and stop typing the cursor runs away to the top of the page. If I try and bring it back down it becomes very hard to type cos it keep returning to the top left of the document.
Has anyone ever known this....?

I've tried reinstalling the system to manafacturing state and still no joy.
I've also the latest Symantec antivirus installed.

I'd really appreciate and be amazed if there's an answer.

Thanking you
fi