"Oh Sweet Jesus what did you do!" (IT HELP!!)

One of my co-workers accidentally copied ALL of his files from his computer to the desktop D: Now We cant do anything except hard shutdown and turn on the computer.

How do I ....
A. Reset the computer to 2 days ago while keeping all of my files.
B. Undo?
C. Get my computer to where I can DO ANYTHING! (Besides start up and shut down)

When you say ALL files? I guess you just mean documents etc....?

Do you have a time machine backup?

If no, then try booting into safe mode Mac OS X: Starting up in Safe Mode and moving the files back from there.

When I say all I mean documents and etc (we are a graphic design company and we have over 10,000 .ai files)

We do have a time machine backup! But I don't know how to activate it without being able to use the interface.

On the Time Machine Backup part, if it's a complete Time Machine backup, boot with the OSX DVD or Lion Flash Drive and from the menu up top, select restore from Time Machine Backup. It will restore to exactly when the last backup was done.

Is there anyway to reset my computer without the flash drive? It is Lion but we dont know where the flash drive is... The guy who sets up out macs pretty much sucks D:

If your machine has the Lion Recovery Partition you can boot holding down Command+R after the startup sound.