How to get Administrator Permission to delete a folder?

[Seahawk]

Hello.

So, I had used antivirus named 'Net Protector' which was detected as a trojan horse by Avast. I have deleted the trojan. But, it had made copies of some files in Disk C and D. The files in C are cleared but the one in D cannot be cleared. A dialog box appears telling that 'Administrator Permission is required'. Now, there's only one account in my PC which is an administrator account. So, what's the problem?

Bye.