My name is Saurabh.
The computer not booting into the windows can be due to a hard drive issue and also due to a software issue. I would recommend you to perform the Dell Pre-Boot System Assessment to isolate the possibility of this being a hardware related concern. And once that happens, and the system clears the hardware diagnostics, should then explore the restore options.
Kindly click the following link to get the exact steps to perform the hardware diagnostics: http://support.dell.com/support/topics/global.aspx/support/kcs/document?&docid=DSN_300428&isLegacy=true
Once that is done, please write back with results. Eager and Glad to assist.
Edited by Orange Blossom, 11 August 2012 - 07:09 AM.
Revealed link and removed spammy content. ~ OB