Hi,
As far as i know, you can use SAP IDM to set password and distribute the password to managed systems.
For shared PC, SAP SSO 2.0 SP05 supports RFID Identification which might be useful in your scenario. See 5.8.8 Identification Using RFID Tokens in SSO guide:
http://help.sap.com/download/sapsso/secure_login_impl_guide_en.pdf
Thanks.
Jim