Computer help please! My Macbook has started acting very erratically. I've done all the usual things to try and fix it - resetting PRAM, running the disc doctor to fix permissions - but nothing seems to be helping. I feel like some sort of nasty malware has got into it and it needs a good hoovering out. What else can I do to try and fix it? Symptoms are - it's running very slowly, the fan is very loud, whenever I open Chrome it now says it's unable to access my permissions, there's some stuff in the bin that I'm unable to delete because it contains things that can't be read or written (error code 36), it's just generally sluggish and something seems to be up. The Macbook is very old and I'm running OS 10.6.8. - it was working fine up until a few days ago. Any ideas?