I have an SL400 and upgraded to windows 7. I installed the operating system and used thinkvantage system update 4.0 to install the drivers. All went well except 1 thing(actually 2) as the Device Managers says there are 2 drivers missing, displayed -->Other devices-->Base System Device(this displayed 2 times one under like 2 drivers are missing).
SL Systems upgrading to Windows7
The Unknown base system device is the Ricoh Card Reader.You can get the driver from the below given link