Windows 7 Corrupted System Files / Windows Explorer Crashes

I (my wife) is running Windows 7 Home Premium (64). Windows explorer crashes when:

-Searching with more than 4 characters in the start menu
-Opening the Network and Sharing Center
-Various other times that seem unrelated

I have attempted:

-Startup repair X3 : it catches problems but doesn't repair them
-sfc /scannow command : also catches problems, and the CDA log shows all of the corrupted files.
-Copying the system32 files from a fresh windows install to fix the broken dll files while in another os : this didn't seem to have any affect
-System Restore doesn't have any images before the issue began
-Full system antivirus and malware scan and rootkit detection with no results showing (doesn't rule it out, but I used Norton commercial, Mbits, Lavasoft, and Kapersky online all in safemode, and some rootkit detectors)
-Repair Install : hangs when initiated
-Updating windows to SP1 : it seems the system attempted to update some time ago and failed or was interrupted. Now SP1 won't install, the updater hangs
-in an attempt to fix the windows update hanging issue, I tried:

-Installing the system update readiness tool (Download System Update Readiness Tool for Windows 7 for x64-based Systems (KB947821) [September 2012] from Official Microsoft Download Center) : the update hangs too
-Installing the fix it program here (Fix the problem with Microsoft Windows Update that is not working) : didn't make a difference
-renaming the software center file as in this thread (Script or command to delete contents of Software Distribution folder?) and re-attempting to install sp1.

I (my wife) has some very expensive programs on her computer that we no longer have install discs for. She had them before we were married, but they seem to have been "lost in the move." We can probably work with each of the individual programs, but I'd sure like to look at other options that allow her to keep her file and program structure intact.