Is your old laptop Windows xp.
If so then everthing is probably stored under c:\documents & setting\yourusername\my documents\my music\itunes\
So install the latest itunes on your old laptop just because it's easiest when it's got the latest version. Then copy all of the itunes directory onto said memory stick or external harddrive
Then on the new windows 7 laptop install the latest itunes. Then goto c:\users\username\my music\ check there is an itunes directory, and then just replace it with the directory from your old laptop.
One other thing. In case your tunes are not all in the one place you should ideally on your old laptop tell it to consolidate the library which copies the files all into the one directory in case they are stored in different locations. If they are in weird places then the odd song might be missing on the new laptop, the consolidation takes care of this.