I have an old Thinkpad R51 and Windows 7 just doesn't give me a Sleep option.
I suspect it's because it's running the default VGA driver. The machine has an Intel 855 GME graphics adapter but there doesn't seem to be a WDDM driver available publicly. Lenovo's driver download page just says that drivers for Vista are bundled with the OS. Apparently, they aren't bundled with Windows 7 as it always defaults to a generic VGA driver.
Is there a reliable way to get Sleep to work on this machine?