I am trying to install a vb6 application. Everytime i start installing it, it shows an error

"There was an unexpected problem trying to create or write to logfile "c:\windows\st6unst.000". Error number is 7"

After I click on OK. It resumes installation and after a while gives the error :

"An unexpected setup error has occured"

and asks to quit the installation

The logfile created by the setup shows the foll:
" Unable to create directory C:"

Please help me with this!!

Thanks
SheetalD