AUTOCHK.EXE corrupted

I have a Dell Studio 1558 running Windows 7 Home Premium w/SP1. Pretty much stock Dell configuration (nothing added by me). Bought in June 2010.

I've looked through many other posts trying to find a complete solution that would match my problem and so far I've had trouble. So, here's my issue:

Last night, Norton Security Suite from Comcast decided to upgrade itself. One of the new (or at least the first time I've noticed it) features is disk maintenance in the Tuneup section. I tried to run this tool, which is just really a link to Windows defrag tooling. Norton returned a message that file system corruption prevented it from doing anything. Also, the Windows defrag tooling doesn't show my C: drive as available for analysis, let alone defrag.

This made me think I should try a check disk at startup. I setup check disk and rebooted. Nothing happened. It just went to the regular login screen. Searching through posts on this and other sites, I found a note about using sfc /scannow at a command prompt to check for corrupted files. the sfc scan identified the autochk.exe application as corrupted - see below.

Could not reproject corrupted file [ml:520{260},l:46{23}]"\??\C:\Windows\System32"\[l:22{11}]"autochk.exe"; source file in store is also corrupted

So, I pulled out the repair disk I made 3 years ago and attempted to boot into the repair tooling to fix the problem. Upon boot up to the DVD, I received an error message (don't have the exact message handy) that pretty much just said error: 0x4 and then a bunch more numbers - more than the usual BSOD string would show. I checked to see if I had applied SP1 or if the system came configured that way and I don't see anything in the Windows updates or add/remove programs lists that looks like SP1, so I'm assuming it came configured that way.

I booted to the repair tooling on the hard drive's recovery partition and ran the repair tooling there. It went through all it's processes and said the a) it had found a corrupt file (autochk.exe) and that it had fixed it. However, upon rebooting normally and re-running the sfc scan, it still says the autochk.exe file is corrupt and can't be fixed. I'm assuming that the recovery partition wasn't smart enough to know it's copy of the file was broken and that it only succeeded in copying a broken file.

So, what are my options? Is there a way I can get a "good" copy of the autochk.exe file and replace the two bad copies on my hard drive (C: drive and recovery partition)? Is there somewhere I can download a new repair disk ISO that works? Do I have to reinstall my OS from scratch (really don't want to)? Is there some other tooling that would help fully diagnose and resolve my issue? I feel like the Windows tooling is just running me around in circles a bit.

The computer seems to be working mostly fine most of the time, but it does have an issue with temperature and the fan runs way more than I would expect. Seems to get worse the more I use IE. I'm in no hurry (yet) to "fix" anything, but am concerned. I would appreciate it if someone could supply more than the pat answer of re-loading the whole OS.

Are you suggesting that the Install disks can be used for repair? Or are you providing this info as a last resort (complete re-install)?

Thanks for the clarification. I was unaware that the install disk could also be used for repairs.

I checked the C:\windows\winsxs\... folder paths and have some more questions:
You pointed me to a folder starting with x86. I have the 64 bit version of Windows 7. Should I be looking for the amd64 folder names instead?
I have 2 folders similar to the one you mention; one dated 7-13-2009, the other 3-29-2011. Do I want the newer folder? (Is the newer folder from installation of SP1?)
I did a quick try of sfc /scanfile on the file you listed and it said "Windows Resource Protection could not perform the requested operation". Do I need to be in safe mode or boot up with the repair disk or something?

Last, assuming I find a "good" copy of the file, to where would I need to copy it in order to resolve my issue?

I'll spend some time on using the install DVD and see what I come up with.

Update:

Burned DVD of Windows 7 Home Premium w/SP1.

Booted with DVD.
- Used DVD to run startup repair - no problems found.
- Used DVD to run command prompt - ran sfc /scannow. Sfc would not run and gave the following message:
- System repair pending which requires reboot.

Booted normally - nothing special happened.

Booted to DVD.
- Startup repair still says no problems.
- Sfc returns same message regarding a pending system repair and doesn't run.

Booted normally. Ran sfc /scannow. Received message that corrupt files were detected but not repaired.

Checked CBS.log. Still same messages about autochk.exe being corrupt in C: drive and in store.

Did some more searching and came across this (yes, I know it's on a Vista forum, but the jist is the same):
Chkdsk will Not Run at Startup in Vista

Followed the instructions to copy just the autochk.exe file over the corrupt one. One thing I noticed (and was mentioned in yet a different forum post) was that the properties>details were all blank except the size and date fields. Once I copied over the "good" file extracted from the DVD, the properties>details were back to normal.

I did a reboot, a sfc /scannow, and initiated a checkdisk and everything worked fine and reported no further problems. So, I spent the day doing a full system virus check, cleaned up a bunch of old temp files and wastes of space, and will be creating a disk image of the system tonight.

As a post-script: C: drive properties>tools and clicked on defrag. When I did this, Windows said that another program had scheduled a defrag and gave me a choice to leave that alone or cancel it. I chose to cancel it, which I suspect was scheduled by Norton.

I went back into Norton Security Suite and looked at the performance tooling. The default settings were to automatically defrag the c: drive and to run the disk check. I have turned these options off and set the performance tooling schedule to "manual".

The system seems to be running well now.

can you please help me to find the right version of autochk.exe and where to download it,when I check the details Size is 759kb and Date 20.11.2010. everything else is blank...