Have you installed any browser toolbar or music toolbar recently?
What is the complete error message?
Have you made any significant system changes recently that could have caused this issue?
apcrtldr.dll is loaded as dynamic link library that runs in the context of a process. The assembly utilizes the .NET run-time framework (which is required to be installed on the PC). The file is digitally signed by Bandoo Media
which was issued by the Thawte certificate authority (CA).
If you have installed any music toolbar recently, follow the steps in the article below to uninstall the toolbar and check if issue persists.
Since the issue is not specific to a particular browser (Internet Explorer or Google Chrome etc.), there could be possibility of some third party program conflicting with the smooth running of the computer.
First, I would suggest you to perform clean boot on the computer.
Putting your system in Clean Boot state helps in identifying if any third party applications or startup items are causing the issue.