LG VX-8550 Chocolate

i got the music pack 2.0 and installed everything several times. i plug my phone into my computer and windows gives me a popup to install it but can not finish installation. so whenever i try to transfer music from my comp to my cell i always get a connect failure message.

about a week ago i put about 100 songs on it and it worked fine then i installed the service pack 2 for windows xp and hasnt worked since

ive turned off firewalls and tried reinstalling
anyone have anything they know might help this problem

thanks