salman327, when you install Windows XP from scratch, it will only have the Recycle Bin on the Desktop. If that's what you're seeing, maybe the upgrade went OK. Do you still have the Task Bar and Start Menu like you should?
You won't need to do any formating from a DOS prompt with Windows XP. The XP install program on the CD can delete, create, and format partitions for you. What I would do if I were you is boot from the XP install CD and delete all partitions on your hard drive. The instructions on the screen when you get to that point in the install should tell you exactly how to do that. After you get rid of all partitions on your drive, you can just hit the ENTER key to have the XP install create & format an NTFS partition and then install XP. It's very easy compared to the old DOS FDISK and FORMAT days.