go to western digitals web site and aquire some diagnotic software appropriate for your HDD. (you will probably need an error code from this software before you can RMA the drive)
A low level format is not an option, this needs to be done by the manufacturer to preserve the file structure on the disk.
If you low level format with anything other than approved soft from the manufacturer you seriously risk permanently destroying the drive.
Have you tried running a full chkdsk from the recovery console? some thing like chkdsk c: /r
Edit: additionally, thinking about it you should test your RAM, it may be your RAM than is faulty an causing these problems so get memtest86 and run that for a few hours.
Intel core I7 920
6GB OCZ platinum 1600
Samsung 1TB F1 Spinpoint
Samsung SM2443BW 24"