Limewire is free in it's basic form and costs US$18.88 for the Pro version which you should only buy when you are happy with the basic and are sure you want to.
I'm afraid your Limewire was bought from a scam site, and it may have been a doctored version which might have helped towards the failure of your computer.
The version you paid for was in all probability, the basic version, which is free of charge at
http://www.limewire.com/english/content/download.shtml This will also be free of anything which is likely to damage your computer!
It is important that you have anti virus and anti spyware sofrware on your computer, and use it with great regularity.
This thread explains a bit about scams
http://www.gnutellaforums.com/showth...threadid=28751
It may be too late to try to get your money back, but it would be worth a try, However it wouldt be wise to cancel your credit card as th spammers sill have the details.