If possible spend a little extra and buy a 60 gb ssd (though you can't have too many programs installed, but for a normal user who doesn't use large applications that would suffice) or a 120gb ssd, and keep your 1tb HDD as a single partition as it doesn't make sense to create more partitions. If you want to lock drives and keep some personal content off prying eyes make 2 partitions and use bitlocker on one. To protect your data you just can't rely on one backup, so you could have bought 2 500GB and used in Raid 1 configuration to mirror the data (you can still buy another 1tb if you think you value your data more than money)
But if you just want to use the current 1tb, then make 3 partitions - 100gb (for OS), and the remaining 900gb into what ever spaces you want (if no one else uses your PC just make 1 partition and store your files in folders). Partitions don't protect data when the disk fails, but can only protect data if your OS crashes and you might have to reinstall the OS.
By the way try seeing some youtube videos and see if you can open your hardisk and fix the head. Sometimes the head getting struck might be causing the issues and fixing it is very easier, just follow the steps in the videos.
