Problem:Any Hardware Not Found In My laptop

No Operating System is detecting Audio,WiFi Lan, and DVD Drive. Currently I m Using XP and Windows 7 Ultimate.Some times Wifi Lan appears and Sometimes not, Sometimes Audio Icon appears to play sound but most of the times No hardware is detected despite all the correct drivers installed, The same laptop was working well 1 week ago. Re-installation of Windows 7 from Hard Disk through XP didnt work.
What is the possible problem and Solutions.