I got two PCs (one a little bit older Desktop and a new HP Probook 5330m LG719 Laptop), both running Ubuntu 11.10.

When I log in on either of them, sooner (sometimes right after login) or later (sometimes 30 minutes afterwards) the whole desktop gets extremely slow. That is, I can no longer use it, the mouse will only move every other second for some pixels, or not at all; keyboard input does not seem to work (at least alt+f4, etc.)

I cannot think of anything that might cause it: My laptop runs on an Intel Core 5, my desktop an AMD Phenom 9650. The former got an Intel HD 3000 graphics processor (rc6 and stuff enabled, which never caused crashes without Skype enabled), the latter a Nvidia GeForce 8400 GS with proprietary drivers.

The only other software I have installed that is not in the standard installation is, as far as i remember, dropbox and google chrome.

Neither in syslog nor in the xorg log are any entries near the time of the freeze. Starting Skype in the Terminal wont give any results, it seems to crash before reporting.

Does anyone experienced similar problems or know a solution for it?