In these circumstances, the operating system rarely gives you any details about the issue, so you often need to find external help to solve the problem.
EMCO MoveOnBoot is an excellent application that lets you move, rename, or delete any file or folder that is blocked in the system, either because another application is supposedly using it, or for any other reason.
The program includes a useful assistant that helps you perform these tasks easily, without too many steps. Aside from that, EMCO MoveOnBoot has more than 20 different skins to change its appearance, and it can be set to launch at startup.
Before deleting any file, make sure it won't cause any irreparable damage.