Freezes in my Dell C521 too, with mouse optical or with trackball. Info: AMD Athlon(tm) 64 Processor 3500+ (Single core) 256MB Ram Ubuntu 6.10 Kernel: linux-image-amd64-generic 2.6.17.10 -- Mouse pointer freezes in Dell Dimension E521 / nForce 430 https://launchpad.net/bugs/67734