Grooveshark should have an FAQ section or something similiar to it to help out the people who use the site, if they dont, try contacting them. It's their duty to help out the people who use their site.
I've personally never used the site, but I searched it...and it has a help page. So, my best advice is to go to their help page, and type in your question - http://funadvice.com/r/14p6mlp1iph
Here is the link that will answer your question, from their help page - http://funadvice.com/r/14p6modag1o