Well, even when you delete DCS World from system there is always a registry file left behind..not always but sometimes..this could be some of the problem..
here are some registry cleaner links..:
http://www.paretologic.com/products/regcure/
http://www.wikihow.com/Clean-the-Windows-Registry-by-Hand
http://download.cnet.com/Registry-Clean-Expert/3000-2094_4-10215506.html
http://download.cnet.com/Free-Window-Registry-Repair/3000-2086_4-10606555.html
this will give you a more indepth idea..
other than that don't know what is going on with your system..