Question : Excel macro needed to find existing text and replace with new text

In an excel spreadsheet I need a macro or ANY WAY to find each instance of a partial url and change that partial url with a different url there are 42000 instances of this same url in amongst other txt so I can't do it manually. Well I can but it will take me forever.
Basically I have a websites price file with countless bits of info of the objects for sale including the url of each object and a url of each objects photo, I need to change all these URLs which all have the same upper level domain name to a differant domain name but leave the subsection of the links which point down to each lower level folder/files in the url etc

for instance I have 42000 urls all with the exact same domain name of

http://www.mydomain.com/this sub section/of the url/is always/ differant/index.htm

I need to locate the http://www.mydomain.com
and replace it with a differant url which will be the same for all the 42000
BUT I need it to leave intact the sub section of the url so it would look similar too the below

http://www.mynewdomain.com/this sub section/of the url/is always/ differant/index.htm
ie only changing the upper level section of the domain but leaving the rest intact and nesting the change exactly correctly to leave it as a valid url.

Hopefully all that makes sense.

Answer : Excel macro needed to find existing text and replace with new text

PS Press Ctrl+H to bring up the Replace dialog!