No, that CPU requires a 1066 MHz bus -- your system supports only 667 or 800. The best you can to is the T7700 -- but these were produced in small volumes, so you may find the T7600 the fastest one you can find, as it was the last produced in large volume.  
I am wondering can I upgrade my Dell Inspiron 1420's processor to T9550 or not?If not,what is the fastest processor that can be supported by this computer?Thanks!
Can Dell Inspiron 1420 support T9550?