Here is an example to find all the references like ..."images/filename.extension"... and replacing them with ..."<%=ResolveUrl("~/images/filename.extension")%>"...

Find: {images/[A-Za-z0-9.]*}

Replace: <%=ResolveUrl("~/\1")%>

Good link for "Differencing Disk" (i.e. creating additional machine from base image): http://arcanecode.wordpress.com/2008/03/04/differencing-disks-in-virtual-pc-2007/