Internet freezes

hi i hope you can help i have a problem with my computer when ever i watch youtube or any other live streaming my internet frezzes and i wont respond, so i have to close it i then get a the message asking me to send a report, when i then try to reopen firefox or IE i get a message that it is still being used and end up having to restart the computer. hope this is enough info for some one to help me many thanks simon