Quote: Originally Posted by MRINAL KANT
When i was using xp it was installed in C but after that i have installed 7 in D and formated XP which was in C .
You could not have formatted XP with the Windows 7 boot files residing there. It would have refused formatting due to the presence of boot files, or else 7 would not be able to boot and C would not have the System flag.
So you likely still have XP on C.
If you would like to have Windows 7 on C as most do, then I'd reinstall to C after moving any data off of the HD. During install delete it and and other partitions not needed, then repartition or let installer do it for you by clicking Next.
If you want to keep Windows 7 on D then convert to Primary, mark it Active, boot into Windows 7 installer to run Startup Repair - Run up to 3 Separate Times
. How to set partition as Primary with partition manager?
posted twice How to Set Active/Inactive partition -Partition Wizard Video Help.
You can then delete C in Disk Mgmt which is how an OS is correctly removed, then either create a new Data partition there, or resize D into the space using Partition Wizard Move/Resize Partition Video Help.
Feel free to ask back any questions for clarification.