Wallpaper, Taskbar, WinExplorer disappeared

I'm new posting here after lurking for quite a while waiting to upgrade to W7. I'm now running Home Premium 64Bit on i7-930, Asus, 12GB (photo editing), new rig less than 2 weeks old. I was trying to copy my old Google Earth 'myplaces' file from my old rig to my new one. UAC, or something, wouldn't allow me access to my Users/App directory. I searched the forums and then, stupidly, started trying to do things with permissions, things I no longer remember.

Now each time I boot I get two errors: one is from Acrobat Distiller saying that it can't create a file that already exists (error 183) and a MS Visual C++ Runtime Error. The error message says "Program C:\Program..." with no additional name or info "has requested runtime to terminate in an unusual way."

My wallpaper has disappeared, all the taskbar icons are gone, all startup items haven't started, I can't get my Firefox shortcut to start the program. Some shortcuts, like to Excel, do work. However, I am denied access to my outlook.pst files so Outlook won't start and MS Word 2003 gives me a dialogue box mostly in Japanese referencing a file 'Omso.ad' in English followed by another Japanese box with only an OK sign followed by a seemingly endless series of warnings about invalid signatures and macros. Actually, almost all my programs will no longer run.

Since there is no program identified at the boot screen I don't know where to start. I tried sfc /scannow but the result was a cmd window open and closed so fast I almost couldn't see it. I tried to remember what I did and go back and undo it, but I honestly don't remember and access to most everything is now routinely denied.

I really don't know where to go from here. I really don't want to have to wipe my disk on this OEM installation. Any suggestions will be gratefully received.

Thanks,
rebadurchee

Ztrucker - I was still installing programs and I hadn't started System Restore, so no go there. I tried to install ERUNT early on because I'd had such terrible experiences with it in XP, but it wasn't compatible with Win7 so I procrastinated. Can't believe I was so stupid.

A Guy - I'll give the repair install a try in the morning when I'm not so depressed and tired.

Thanks to both of you!

Rebadurchee

Yeah, me, too. The system somehow prevented ERUNT automated backups from happening. I did one manually shortly after I installed it, but it doesn't show up in the ERDNT folder.

I also did a manual registry backup in Revo Uninstaller, but I can't access the Users directory to find it.

Will a repair install reset all the permissions as they were or as a brand new install of Win7? Does that mean I will have to reinstall all my programs? Is there no other way to reset permissions?

A Guy - I've managed to create a new user with Admin privileges and so far programs work. I'll slowly migrate only the absolute essentials over, like .pst files and iTunes music, then reconfigure everything else. It's a glimmer of hope. Thanks for the ERUNT script, it works perfectly! And thanks for hanging in with me.