chkdsk every boot - new hard drive

I have a Lenovo T500 laptop running Win 7 Pro x64. The hard drive started to fail (chkdsk showed bad sectors, S.M.A.R.T. test failed, etc.) so I got a replacement drive on warranty from Lenovo, put it in, reinstalled Win 7 and about 150 updates, restored my backed-up data, and reinstalled several applications.

At some point in that tedious process, chkdsk started running on almost every reboot. I have run chkdsk /r both normally and from the Restore Environment.

When chkdsk (with or without the /r switch) runs, it finds NO problems. I have also run the hardware disk check, which includes a couple of SMART tests, from the "Lenovo Toolbox," and that also shows NO hardware problems.

Usually (but not always), on the boot immediately after running chkdsk /r, fsutil shows that the Dirty Bit is clear. However, as I continued to install applications -- which require reboots -- the Dirty Bit gets set and chkdsk again runs on every reboot. Sometimes, merely switching between user accounts causes the Dirty Bit to get set.

[This may or may not be applicable, but in order to get a proprietary add-on to IE 8 to install properly, I had to call tech support for that add-on and they disabled DEP as part of the install.]

I've used chkntfs /x to prevent chkdsk and then scheduled a chkdsk /r. I've run chkntfs /d to restore default behavior.

Event viewer is throwing a ton of NTFS Event ID 55 errors.

I've seen some posts on Event ID 55 that suggest it has something to do with Avira. I'm using eSet NOD32 ver 5. I've also seen suggestions to change the power plan to keep the drive from going to sleep. I'm a bit reluctant to setting it that way for a laptop -- but it's better than having to reinstall everything again so I'll try it and repost if any change.

[Edit: it's very unlikely to be the disk going to sleep or powering down, because of the following observations:
(1) run chkdsk /f
(2) on reboot, run fsutil and see that Dirty Bit is not set
(3) switch to other user account -- without going to sleep/power down
(4) run fsutil and find Dirty Bit now set]

I can't think of what else to do other than to wipe and start again.

Assuming that the issue is NOT a hardware problem, if I make a system image at this point, run something like DBAN to zero out the drive, and then restore the image, is the file inconsistency likely to return?

Or -- and I'd really rather not have to do this -- should I zero the drive, reinstall Win 7 from DVD, download and install the 150 Windows updates, restore the data from my original backup, and reinstall the various apps I need?

If I do either of the above, should I use DBAN or the clean command using Diskpart?