Powerdvd is a media player as far as I know, you can try uninstalling it be I doubt it do any good. Your cd sounds really scratched, I have a alternative for you though. You can legally download from blizzard. However, you will need a blizzard account. Do you have one already? And by the way, to get the cd, you will need to enter your cd key on the site. I only recommend this if you are about this, some people get nervous with entering cd keys when there online. But here...
http://us.blizzard.com/store/?rhtml=y
Create a account, then you will need the sc cd key. Once you make an account I think you have to go to your games list to register the cd key. I registered by d2 cd keys(since my disk are really scratched) and it gives you a "new" key. It changed the 16 character key to 26 character, I am sure this happens with sc also. I don't believe you can register broodwar as it does not come with a key( my doesn't at least it's older than me!
If this is confusing just post back for help, I'll be more than glad to walk you step by step.