AHT doesn't complete

Hi All

Ever since getting my late 2011 MBP (on 10.7.2) I've had intermittenent freezes/hangs (login screen, resume from sleep and in Safari) resulting in forced shut downs with the power button. This happens with the 4GB (x2 2GB) stock Apple RAM, 8GB (x2 4GB) Crucial RAM and 8GB (x2 4GB) Samsung RAM. The Crucial and Samsung RAM was purchased new.

I've used AHT (both short and extended tests) with all three RAM configurations and it never completes a single test. It checks the "memory", advances the progress bar and then moves onto testing the "logic board" (and spins the fans for a while) and then advances the progress bar to around 95% complete with the message "Testing in Progress". At this point AHT seems to hang - the mouse 'stutters' across the screen (one to two second delay with no smooth motion) and clicking the "Stop Testing" button or using cmd+period (as instructed on screen) doesn't stop the test. The "Total Time Testing" field also stops counting. I have to force shut down with the power button every time.

I have left the tests running overnight and it never completes or shows an error code.

I have used the third party Rember RAM testing tool on all three configurations several times. It never identifies any issues.

I have verified the hard drive and permissions when using all three RAM configurations. No errors/broken permissions were ever found.

I have no external peripherals of any kind plugged in when testing.

So.....

Question One: Is it safe to rule out a RAM issue?

Question Two: Does AHT test the hard drive?

I ask as I downloaded the SMART Utility app. Its initial scan on first loading the system said that the "Overall SMART Status" was "FAILING". I had one "Pending bad sectors" but one "Removed bad sectors". It had counted a total of 5103 errors on my hard drive with the "Last error type" being an "Uncorrectable error".

When AHT does hang and I put my ear close to the keyboard, it does sound like the hard drive is trying to write to the drive or move something to do with it every two seconds. For information, I have used 50GB of the 500GB Seagate hard drive.

Question Three: Is it the hard drive (or something to do with it) that is causing AHT to hang towards the end of the test?

I cant get to an Apple store for two weeks, so any thoughts on the matter would be greatly appreciated.

Thanks,

Chris