Windows 7: export registry

I have 2 hdd, a}hdd 160 giga-win 7
b) hdd 250 giga win 7
Note The program content of hdd a not same with hdd b

Can I export reg file from hdd b and merge it to hdd a ??
I do that because hdd a running in unormaly and hdd b run Windows 7 smooth and very normal with no problem.
so,anyone suggest me !

Short version: no

Long version: the registry is an account of everything that makes up your computer and how it works. If it doesn't match up properly with the OS installed on your computer, it will not run properly if at all.

Even hdd a and b in the same computer with same hardware ??

Do both computers have exactly the same software installed and the exact same driver versions?

Well,one computer with 2 hardisk,same driver,same os but diferrent software in every hdd .