I was working on a Thinkpad R40 today that wouldn't boot. It would power on but do nothing else, as if it had no RAM. Removing one of the RAM chips solved the issue. The offending chip was a 333Mhz DIMM where the other was a 266. Why would this combination cause a failure to boot? I put the same combination of DIMMs in a Dell Latitude C640 with no problems.
When it comes to ram the fastest ram has to go in the first slot if the 266 is in the first slot you need to remove it and place the 333 in its slot and place the 266 in the second slot it should work then if not I am sorry.