Checkdisk Hangs Every Time. Disk Reports OK?

On Vista Home Premium, I've set Chkdsk to run but each time it hangs about three quarters of the way through step 5, at the same cluster each time. I've run the harddisk tests (SMART, surface scan etc) from the computer recovery console and it passes every test OK. If this a physical problem with the drive or a file system one? If it's the latter why can't Chkdsk fix it? It's a new computer should I go through the hassle of returning it to the manufacturer?

P.S. History: it's a brand new Lenovo laptop. When I first switched it on, it gave me that "Vista didn't shut down properly last time" screen, but apart from that everything seemed OK until I got most of the way through all the security updates, cleaning up all the bundled software etc and Windows Update blankly refused to install SP1. I tried a system restore and that told me there was a disk error and to run Chkdsk. Chkdsk refused to run (something about the drive being locked) and in the end I did a factory reset. This is OK in that now all the updates have installed and there are no more errors, but I wanted to double check the disk, so invoked Chkdsk and... see above.