Unfortunately, this cannot be done through the registry, the search url is
hardcoded into the dll library %systemroot%\system32\shdoclc.dll. Use a
resource hacker to hack the file. Navigate to the string table 76, Element
1211 and substitute e.g. http://www.yqcomputer.com/ %1
for the auto.search.msn.com url.
After saving the file you have to restart Windows Explorer. So crash and
restart Windows Explorer through the task manager. After the restart you are
ready to go, just type two or more words into the address bar of WE/IE and
it will start searching for those words on google
You can also remove the unsafe-activeX warnings that appear on some
websites, but that's up to you.