need to format pc if motherboard changes ?

Hello,
I have two pcs with different Asus motherboards.
One of them has Asus P5LD2 VM and second one has P4GE-MX and both have pentium processor. Now I want to change hard disk from one to another. So will i have to format hard disk so as to work in P5LD2 VM ? can i just remove drivers of old one and install drivers of P5LD2 VM ? I have been told to format the hard disk so as to make it work in other pc. But i do not want to spend time formatting my pc. So i want to know wether it is possible to just uninstall old drivers and install new drivers. if not then where does the issue come ?

hello,
No replies till now .... Let me know if i have post in wrong forum...