fix cannot copy / paste files in windows xp, vista, 7

This is caused by AppInit_DLLS. Usually by installing toolbars like babylon, mystart increbibar etc.,

Removing AppInit_DLLS
Caution: While these steps should be safe to perform if followed correctly, you should never edit the registry if you don’t feel confident or are unsure of what you are doing.

Important! Close all Firefox, Opera and Internet Explorer windows.
Click Start > Run…
Type “regedit.exe” and press OK.
Get to the following location in the registry: HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Windows
In the pane on the right-hand side of regedit you should see a String called “AppInit_DLLs”
Take note of any value listed to the right of “AppInit_DLLs” as it may indicate you have malware installed.
Right click on “AppInit_DLLs” and choose Delete.