Our team has been using the following script to restart services on the front end servers. Sometimes restarting just IIS does not fix issues related to update GAC or features/solutions.
@echo on
net stop "Windows SharePoint Services Administration"
net start "Windows SharePoint Services Administration"
:: net stop "Windows SharePoint Services Search"
:: net start "Windows SharePoint Services Search"
net stop "Windows SharePoint Services Timer"
net start "Windows SharePoint Services Timer"
net stop "Windows SharePoint Services Tracing"
net start "Windows SharePoint Services Tracing"
:: net stop "Windows SharePoint Services VSS Writer"
:: net start "Windows SharePoint Services VSS Writer"
IISRESET /restart