All of a sudden my machine has become incredibly slow to boot up and to launch anything - boot up took over 5 minutes and launching an app like Mozilla or OpenOffice can take just as long. All the while the harddisk drive light is burning constantly. It is as if there is some process that never completes, takes a long time to time out and restarts itself whenever I launch an app. Once I'm in, apps seem to run fairly normally. I've looked at 'top' and can't see any culprit there. I had this happen once before and it was solved by making sure that nothing was plugged in to a usb port while booting up or even logging on. The last significant things I have done prior to this happening do a normal update and upgrade using Synaptic and install Liferea.