I have given the clustalw (*.aln file) as input and given the submit button,but it doesn't shows any alignment result or images? How to view the output files?
I'm not familiar with that web server, but you can visualize the .aln file using a platform specific (win, mac, etc.) version of ClustalX that can be downloaded from www.clustal.org/dowloads/current
also here are the sample instruction from the server you reference above
just replace the vp7.aln file with your file of interest. It appears that the results are presented in a pop-up window that is launched from your browser, make sure your pop-up blocker is disabled for this purpose.
Save the alignment file vp7.aln on your disk, and upload it in the first section Aligned Sequences of the form.