Explorer.exe infection

Avast just popped up wanting to send my explorer.exe to virus chest?
Am I wrong in thinking I cant let that happen?
Is there a way to replace explorer.exe, or repair?
Any help would be greatly appreciated!
Thanks

Oh, XP pro, up to date service pack and updates.

If you can attach a screenshot of this alert, right click the avast tray icon and select ‘Show last popup message.’

Or post the full details of the alert, including the location and malware name given. If explorer.exe is in a different location than normal then it can be an indication of an infection.