First thing to do is to check this page: (first hit on Google) http://www.logitech.com/en-us/441/270
That page is also available in many localisation and languages.
You may try installing the updated drivers. From the page above, click the Download button, sellect your OS and wether you want the 32 bits or the 64 bits version. On a modern computer with a 64 bits OS, you want the 64 bits version. Hint: If you have more than 4 Gb of RAM installed, you DO HAVE a 64 bits system.
Electro, January 2012