Those who have come across files don't delete, here are some suggestions to try.
1. Make sure that the file attribute is not READ-ONLY.
To unset read-only, do this:
[*]Right click on the file you want to delete and select Properties.
[*]Select the General tab.
[*]Uncheck (untick) Read-only box.

[*]Click OK to apply the settings.
Then try deleting the file again.
2. Delete the file in Safe Mode. Make sure that the file is not READ-ONLY. Refer to step 1a to 1d to figure out how.
3. Change the file extension.
[*]Open My Computer.
[*]Go to Tools > Folder Options.
[*]Select the View tab.
[*]Scroll down to Hidden files and folders.
[*]Uncheck (untick) Hide extensions of known file types box.
[*]Click OK to apply the settings.
[*]Close My Computer and open it again.
[*]Locate the file you want to delete.
[*]Right click on select Rename. Notice that the file name is something like this: whatever.exe. Change exe to something else, like old or txt.
Try deleting the file again. You can do this in Safe Mode as well. Make sure the file is not READ-ONLY.
4. Use
FileASSASSIN.
5. Still can't get to delete it, set the permissions right.
[*]Right click on the file that you want to delete and select Properties.
[*]Select the Security tab.
[*]Click Advanced. A new window will open.
[*]Select the Owner tab.
[*]Click on Administrator. Click OK. You will be back to file properties window.
[*]Now, click on Add.
[*]In the Enter the object names to select (examples) textbox, type in your username. Then click on Check Names.
[*]Click OK.
[*]In the Group or user names list, click the account that you want, and then select the check (tick) boxes of the permissions that you want to assign that user. Check (tick) Full Control is the best.
Try deleting the file.
6. Still cannot, create another account with administrator rights, drag the file to the new account and try deleting it. Remember to log off, not switch user. If you use switch user, you might get a "file is in use" error.
[*]Go to Start > Control Panel.
[*]Change it back to Classic View if you are using Category View.

[*]Double click on User Accounts.
[*]Under Pick a task..., click on Create a new account.
[*]Type in a username.
[*]Select Computer Administrator and click on Create Account.
7. End Explorer and take note of where the folder where the file is located.
[*]Press Ctrl + Shift + Esc to bring up Task Manager.
[*]Right click on explorer.exe and select End Process Tree.
[*]Your desktop will be gone.
[*]Go to File > New Task (Run...) and type in cmd.
[*]In Command Prompt, type in cd folder location. An example is cd C:\Whatever. Then type in del whatever.exe
[*]Repeat step 7d to bring back your desktop, but instead of typing in cmd, type in explorer.exe.
8. Use
Unlocker.
9. Still, if it fails, reformat and reinstall Windows. This is guarantee to work, except that instead of deleting one stubborn file, you delete all the files and reset your PC back to factory state. Remember, backup all your stuffs before trying this last method.
Note: This is only for files which give errors like "file in use" error. If you can delete a file, but it keeps coming back, then you have malware, not stubborn files.