All mice used on desktop machines, are same type, MS Intellimouse Explorer + latest Intellipoint software ( I did tried without IP with same results). On laptop I used its own pointing device.

I don't think that a mouse cause this slowness, IE6 and all other apps work great. I've read many similar user reports in newsgroups and MS own blogs.

leighsword wrote:
Internet Option -> Reset...

I did that without success...