Not bad, let's dissect the code.
First your comment is misleading:
##Windows,Mac and Linux file Searcher. #######
##Tested on windows #######
##with a few changes can work in mac os and linux.#######
It's not a Linux or Mac searcher if it needs modifications to work on these systems.
Import statement is not separated from overall code.
Print has no space after it.
You don't really need to capitalize the drive letter...
Variable names are meaningless:
for Dir_ in Dir:
I have no idea what is Dir_ and what is Dir...
Overall you need to read about Python conventions here:
http://legacy.python.org/dev/peps/pep-0008/In general - not bad. Could have command line args for power users tho. +1 anyway.