Windows 7: Nothing starts: Safe Mode can't help me

I have a very enthusiastic wife who kindly took a damp cloth and vigorously rubbed my keyboard over to clean it, WHILE THE SYSTEM WAS RUNNING.
Once I wiped my eyes of saline solution I found loads of problems. It took me some considerable time to actually get the sytem to boot. Boot manager not found on startup but doing a repair mode startup I can now gain access.
Problem is that as soon as the desktop is loaded it goes to an immediate "Explorer.exe not working" notification with ntdll.exe as the fault problem.



I've made loads of searches and carried out countless potential solutions for this and I'm still not much further forwards.
I would just do a system update from a disc to put all my drivers and operating sytem stuff back in place however it won't allow me as the explorer.exe problem locks the system so nothing will start up or run.
Going into Safe mode is still much the same. I can at least browse and find the contents of the hard drive but can't run any programme or install any other software to troubleshoot the problem.
I've tried all the usual, ie system restore etc and even copied some backup opertaing files from a command prompt before the system starts up which did give me some speed gain at startup but it hasn't resolved the main problem.
Most solutions seem to suggest doing something that involves an operating system that actually starts and allows things to run.
Mine doesn't allow anything, or at least nowhere near enough although some few things do seem to work in safe mode but nothing useful.
As the driver has some very valuable stuff on it such as my Revenue accounts stuff I really can't afford to do a clean reinstall.
If I could do this with the contents saved to windows.old, as they used to be on older OS's it might be feasible as long as I could actually run the original programme from the windows.old folder but I guess this wouldn't work.

I've almost given up on trying to do a repair job and am looking at any other suggestions.
Could I just install Windows 7 on another hard drive, so that all the basic operating system files are uncompromised, then copy the contents of the system files to the old drive replacing the old non operating files?
I have another 2 drives on the computer that I could do this from.
If this seems to be a reasonable solution do i need to gain access to the registry files from the old system and maybe copy some of the entries relating to my HMRC (inland Revenue) installation into the new registry and how would I even do that anyway?.
Any other help would be appreciated as I really need to com,plete my year end for the Inland Revenue or suffer some severe financial penalty.

Please run the first 3 free diagnostics listed here: Hardware Diags
They are bootable, so that will be easier than trying to do anything in Windows.
Please start with the bootable antivirus stuff, as that's what this description reminds me of.

You can install another copy of Windows 7 on another drive.
First, make sure you scan for viruses.
Then be careful that you don't overwrite anything that you want to save from the old installation.

I'm not familiar with the Inland Revenue stuff, but most programs have data files to store the data. So you can install another copy of the Inland Revenue program and then use the data file from the old program. I'd suggest posting for help in the General forums for assistance with the Inland Revenue program.

You may try sfc /scannow, in a cmd line prompt.