First time i launched bitcoin i couldn't receive anything and hard drive ran intensively for hours.
I thinked it was buggy but it's not, bitcoin have to get all the known blocks (around 65500 for the moment).
So if you have the same "problem" don't worry all is ok, you just have to wait.
Bitcoin "syncs" the file, so the file get's rewritten to the harddrive every time it gets a block, that's quite intensive.
Having a SSD hard drive right would really speed things up.