I delete explorer.exe by mistake,how do i fix it back?

You can get it back out of your recycle bin.

just restart windows. no biggie. I do it all the times to trick my friends.

reinstall windows, thats the only way

Deleting explorer.exe isn't the end of the world. Restart your computer, and a brand-spanking-new explorer.exe will appear as if by magic.

http://www.microsoft.com/windows/ie/ie7/ie7betaredirect.mspx this is the new windows explorer 7 & it's more secure

try to do a system recovery, recover it back to before the date that is incident happened

hit cntr+alt+delete again, then application tab, then new task. type in explorer.exe, then hit ok. there you go

You may be in a real pickle here, because explorer.exe is the Windows GUI.... the software that draws the screen, responds to mouse clicks and everything. So whatever you do, you'll have to do from the command prompt. You could boot off your Windows CD and during the boot, repeatedly press the F8 key to get into the boot options screen. From there, you can choose to boot in safe mode with the command prompt. At this point, you'll see your computer hard-drive, CD ROM, etc. You might be able to get a copy of EXPLORER.EXE off the install CD. (It will be compressed, so you'll have to use the EXPAND tool.) It won't be super super easy. That's for sure. You could reinstall over your current installation. That way, you wouldn't loose any software settings. But I've always found reloading over an existing OS to be frought with peril! Finally, you could use the REPAIR option by booting off your install CD and pressing the F8 key. Good luck!

Restart the pc and it will return. I suggest you don't do it again. :)