Hi ,
Following uninstallation of HANA studio, try deleting the following folders
.eclipse
hdbstudio
under C:/USERS/<<uname>>/
and try installing again.
Please go through the following links for more details
http://www.experiencehana.com/thread/2291
http://www.experiencehana.com/message/2526#2526
Thanks & Regards,
Krishna N