Error-50 on my Mid-2009 Aluminum Unibody 13" Macbook Pro

Certain websites won't connect to the server (such as Google, any Apple pages), cannot empty trash, cannot copy files from Time Capsule, Disk Utility won't open, slow start up, cannot save work in Pages. Restarting a bunch of times sometimes helps. When it logs into my profile icons on the dock don't always show. I have formatted my hard drive repeatedly(before the first format Disk Utility indicated the hard drive needed to be repaired) and updated to Mavericks. I am at a loss. My computer is unusable as is. Can anyone help?