Can't Click on Certain Items

memtest86 is a good diagnostic but no diagnostic is as stressful on memory as just using the computer heavily.

If you've run 6 clean passes though, I'd say it's unlikely you have a (computer) memory problem.

Not wanting to throw good money after bad, I wanted to try to determine if the HD was really the issue. Here are a couple reasons to think it is not a HD issue:

1) When doing a complete reinstall of Windows with the Factory DVD, the problem presents itself again right away. (Why would that very particular problem arise so quickly?)

2) When using the downloaded iso recommended on the tutorial for a clean reinstall, I had difficulty proceeding beyond the part that asks about language/keyboard. I could not click on the "Next" button on the "Install Windows" window, the top bar of which flashed between blue and grey and then turned solid grey.

3) Also, I ran WD's diagnostic test on the HD again without it showing any errors, and I then used the tool to replace all the data on the whole drive with zeros before doing the second reinstall.

From my amateur perspective, it seems like it is not a issue of OS set-up since it occurs both during install and also after a factory reset. And it also seems like it is not an HD issue. I tested the memory extensively (20 passes or something). Could it be something like the motherboard going bad?

For the original problem of not being able to click on things, what kind of mouse do you have? Wired PS2/USB or wireless?

Can you try a different mouse?

Could you borrow a hard drive from a fried just test with?

I have a wired USB mouse. I will try to get a hold of another to try. With regard to the HD, my non-expert/commonsense judgment is that the fact that the same very particular problem arises again very soon after a Factory OS reinstall on a drive with just zeroes on it suggests that it is not the HD. Is there some reason to think that such a specific problem would reoccur due to a HD issue? And that a problem with the HD would affect working from a bootable install DVD?

Just now, I managed to get a clean OS reinstall done, and so far the problem has not presented itself (after light use).

Could it be something where Windows is silently updating a driver or something like that that is fouling up the functioning of the OS even soon after a reistall?

UPDATE: My reinstall is still working well after adding some key programs (CrashPlan, Dropbox, Office 2010) and using the computer for a few hours. This time, I made sure not to let Windows add any optional updates at all. We'll see if that lasts.

Good news that you seem to have the problem under control but be aware that the system has corrected errors on the HDD so it would seem that there was/is a problem with your HDD so if your not going to replace it make sure you are constantly backing up your data just in case you suffer a failure