I have a Toshiba 460CDT Satellite Pro and have recently upgraded the memory from 64 to 160 RAM. Unfortunatelt there appears to be no improvement in performance. It runs slow and takes an inordinate length of time to navigate from programme to programme and function to function. The hard drive space shows that there is 1 gigabyte free-space. Can you suggest how we might improve the performance or how we can check why it is not performing at anything like the speed anticipated or required?