Windows 7: Need Disk Diagnostic Tool

I've experienced some strange events on my computer and I thought the first thing I'd do is run some disk diagnositc tools. I have five physical disks:
C: system/program disk
D: backup of C
E: data disk
F: backup of E
G: Spare disk ... using as 2nd backup of C

Since C & D are Western Digital devices, I downloaded one of their LifeGuard Diagnostics: DLGDIAG for Windows, and ran the "Extended Test" against C, D, and G. All passed. The control panel says that SMART status is not available -- I forgot how to turn that on (as far as I know, it should work with all five drives).

Any hints on a more demanding disk test that would not wipe the disk clean ... I do not want to have to reinstall my software because of the test. For what it is worth, I'm using Acronis True Image to make image copies of C to D and G.

Suggestions appreciated!

The disk manufacturer's tests are, in my opinion, the right ones to use.

I've heard that Seagate SeaTools will run on any HDD but, haven't tried it myself.

I would recommend to use each manufacturer's testing program.

You can turn on the HDD S.M.A.R.T. function in your BIOS.

Any clues as to what strange events are ? how are you sure theses are disk related ?

Here's a list of HDD tools and some commentary on the process. HD Diagnostic

You S.M.A.R.T. function should be, as Dave said in your BIOS, maybe in the boot order section or HDD priorities.