WD20EARS-00S8B1 2000.3 GB suddenly malfunctioning and can't do checkdisk on it!

My WD20EARS-00S8B1 2000.3 GB Caviar Greed suddenly was not operating properly and reporting strange things - both as to size and in SMART [uncorrectable sector count]. For some reason it is the ONLY drive [of many] on my computer that won’t allow a checkdisk to be done. It reports some error code [too fast to copy and wouldn’t know where to look it up anyway] and says that ‘some recent software’ is likely causing the problem. I doubt it…as it is not on other drives and no new software has anything to do with drives. Anyone know how to try to repair this disk and find out if it is OK or not; data lost or not? Thanks. Also, not connected, but an aside. I have many WD SATA III Black Caviar drives. They PERFORM VERY WELL, but one suddenly crashed and died [in seconds]. When I took it to my local [expensive] data recovery place they were unable to recover more than about 1% of what was on the disk and they told me that WD SATA III drives were especially unsuccessful when it came to data recovery…

Twice I have run the WD diagnostic software long test [on the short test it says it passes] and it runs for about 5 hours until it is about 65% trhough and stops both times at the exact same sector! Please, someone suggest some way to figure out what is going on. Still can not run checkdisk. Any third-party software to suggest?

Recuva has worked for me in the past, but in this case I think you will need to contact tech support.