My laptop Dell vostro 1015 won't pass the dell logo in window 7. Whenever i start my laptop dell vostro screen appears wth loading completed and den immediate black screen. After dat powers become off and d same process repeats... Please give resolution.. thanks in advance

Run the dell diagnostics... hold Fn while booting and run full diags. After which, call dell with results, even if it is out of warranty, they will still help diagnose the issue.

Also, you can try booting with a Linux Live CD to see if you can get it to boot at all.