It depends on your laptop and the motherboard in your laptop. "My laptop actually runs on T7400 and T7600 seems to be the only alternative upgrade for it." have you not just answered your own question? Youi need to check with the manufqacturer of you laptop
The motherboard is based on Intel 945 Chipset...
board manufactures can and do limit ro exploit the features of intel chipsets. Thats why you get the same chipset on many boards with different features. Intel will only give you compatibility list for their boards. Therefore you still need to talk to the computer or motherboard manufacutrer.
Also just a note, even if i could tell you what CPU would be compatible i wouldn't be able to do it just form your description "Is there any upgrade alternative CPU to T7600 ? My laptop actually runs on T7400 and T7600 seems to be the only alternative upgrade for it." There is no usefull information there, I would need to know the laptop model and make and even better the board model and make.