about rohanclient.exe

Short answer: It is not a virus or trojan. It is a hacked rohanclient.exe that has been edited to work with some kinds of private servers.

Long answer: In order to make rohanclient.exe work without gameguard or to enable certain kinds of hacks, machine code is inserted into the rohanclient.exe file using a hex editor. When you do that, the code of the program no longer matches the checksum stored in the Win32 PE header of the executable program when the program was originally created.

Antivirus programs are sensitive to differences between the program's calculated checksum and the value stored in that PE optional header (mine is hacked this way and no longer matches its original checksum value of 0x42D122).

When an antivirus program sees this difference, it assumes a virus is attached to the exe file and usually puts it into a quarantine until you can examine it.

Look in your antivirus's quarantine. If you see it direct your antivirus program to restore it and add an exception for it.