Well, this one is new to me, and although I've googled far and wide, and found others talking about similar issues, I haven't discovered a fix.

Last night, as usual, I hibernated my computer and walked away. Sometimes the charmers at Microsoft decide to install updates and restart my computer without telling me instead of hibernating. That appears to be what happened, because this morning I turned my computer on and it did a full start up.

When it got all started, the problems began. First, there was an update "ready to install" --the notifcation is gone now and I didn't note the numbers, but there were 3 and they were .NET runtime security patches, all 3. I tried to let them install a couple times, and one at a time, and they failed each time.

Anyway, as it started I got a couple errors about not being able to start python. I'm not sure which programs use python, but I use google desktop so that was probably it, although the google sidebar opened, so maybe it was the indexing service or something that failed to load.

My startup programs ran, including Skype, but not including Dropbox which normally starts automatically.

The first thing I did was try to start a web BROWSER. It did nothing. I thought maybe it was just startup silliness, so I waited a moment, and tried again. I clicked, it flashed the waiting icon as though it was doing something, but then it did nothing.

I tried Firefox, Chrome, eventually IE, then I fired up the task manager to watch what happened when I clicked the icon. Nothing happens --I click, it thinks for a sec, then does nothing, and nothing shows in the task manager.

I tried to run Word, Excel, Photoshop, a few other things, all the same. I tried running a time organizing program I wrote in C# and that actually WORKED, but I don't know why. Thought maybe the .net program running might be a clue. Also interesting is that even though Dropbox didn't load on startup, I could launch it, it's up and running without an issue.

Two rundll errors came up as I started up-- one was about an error loading GoogleServivces.dll and the other was about GrooveUtils.dll, both said "invalid access to MEMORY location."

I began to tinker and read up on fixes. I ran a registry fix I found online to make exes execute properly, but that did nothing. I read about a virus that changes the exefiles/shell run command in the registry to load through the virus file, so I checked that out but the entry looked clean (something like "%1" %*)

I read about someone else who mentioned not being able to open Word, but that if they clicked on a word document, it would open. I tried it, and yes, if I click a word doc, Word will open.

Also a little interesting possibly, is that when I try to launch Excel, it gives a message box titled "Error": The operating system is not presently configured to run this application. No other programs give that message when I try to open them.

Windows Explorer will run and windows search runs. my rundll.exe is where it should be.

The latest development that allowed me to open arbitrary software on this computer (I'm writing this message now on the borked computer), is that if I navigate in windows explorer to the executable, say firefox.exe, and I right click, then click "Run As," I'm presented with the option to run it as the current use or another user. If I leave it on the current user, and uncheck the option to "protect my computer and DATA from unauthorized program activity" then any program will run.

Did something get corrupted during an update? I run Avira and Online Armor, but I shut both down to rule those out as stopping the programs from executing.

I'm at a loss, not sure where to go. I think I have my windows CD around, but I'm sure. I REALLY don't want to wipe it, because there's so many settings, and SSOOOOO very much data I'd have to backup, it'll be very, very painful. I'm hoping for a fix other than the nuclear option. What do you think?Find your XP CD...
Go to Start/Run and type in sfc /scannow and hit Enter...
Let it run to completion...remove the CD and re-boot.

Report back with your findings.Ok, I did what you asked.

When sfc completed, it closed and didn't say anything more. Nothing was different on my machine, so I restarted.

On start up I got two error messages in a row from Dropbox:

Invalid access to memory location.
LoadLibrary(pythondll) failed

C:\Documents and Settings\Username\Application Data\Dropbox\bin\PYTHON25.DLL

notepad would sort of open--I'd see a flash of it, and whatever file I'd opened, but then it would close immediately. Tried opening via file, and opening via Start>run. I opened it on the cmd prompt and it ran fine.

Browsers won't open now using the Run As method that worked before.

Update notification is back, trying to get updates:
KB974417
KB979909
KB982168

All of them failed once again.

As I was trying to execute firefox from the command prompt, FF opened on its own, I guess from a previous attempt that I thought failed, but was actually just severely delayed?

I did DISCOVER that I can reliably launch whatever I want from the cmd prompt.

Any clue what's going on?Did you try system restore?