Once a different OS is installed the Dell recovery partition (F8) is no longer useable and you will have to manually install with discs.  You can download the version of Windows 7 you had from Microsoft (on a different PC), create an ISO bootable DVD from the download and use that to boot and install Windows 7 (use the original Dell Windows 7 product key from the sticker on the PC).  You will also need drivers for some Dell specific items such as the sound and they can be downloaded at www.support.dell.com  The original audio problems could have been corrected, and most likely without reinstalling the OS.  
Hi Guys,I bought a Vostro V131 machine (with Dell Mobile Broadband) last month. The factory installed audio drivers were giving trouble and there was no audio while playing audio video files in any of the players like WMP, VLC, GOM etc. So instead of restoring to factory settings I installed the Windows 8 Developer Preview by formatting the C Drive and without creating an image.Now the situation is even worse and most of the drivers are giving trouble infact drivers for the Finger Print Scanner, WebCam and Mobile Broadband are not even getting installed (Error Message - "Incompatible Windows Version") . So again I want to rollback to the original Windows 7 64Bit OS (Factory installed) but I dont see the option of doing a factory restore after pressing F8 at the time of booting.I do not have any restore image or DVD with me. How do I restore to the factory installed Windows 7? Thanks in advance..
Windows 8 Developer Issue