How to repair a strange error in my computer..?

Yesterday I downloaded game Crazy Chess 1.0 in web download3000.com by IDM , it operated well .But I can't creat shortcut this game.I tried to creat shortcut.Then I opened IDM , clicked 'open with' ,it appeared with a window which was include some programs on the desktop such as:Notepad ,ACDsee,Opera,IE7...I clicked IE7 ,extraordinarilly,all symbols of programs on desktop were changed into IE symbol.I can't open any programs event Kaspersky, window media player...,except IE ,Recycle Bin.,,E.g I click MO Excel ,it evolves a window with Warning:

" File download -Security Warning

do U want to run or save this file:

Name:EXCEL.EXE

Type:EXE File ,17.0 MB

from:C:\program Files \Microsoft Office \ Office12

Run save cancel"

I click Run this process happens again.Click save ,it notifies : Download complete ,then this process happens again. Help me!!

How to repair a strange error in my computer..?virus removal

Try to visit this website, I just came accross a lot of info on pc maintenance %26 repair :

http://pc-maintenance.blogspot.com

How to repair a strange error in my computer..?anti virus protection

Id wipe the harddrive and reinstall windows.
Restore your PC to yesterday