winavi trouble

i have been using winavi 7.1 for months with no problems.starting today,ever time i try to convert a file i either get the error message"can not render the graph,"or "winavi could not detect vob".ive tried uninstalling it and then re-installing it but the message remains,i even tried earlier versions of winavi but still same error message.so i'm giving up on winavi,at least for now.can anyone recommend a fast,simple video converting software?i've made no change to my codec pack(k-lite mega codec pack")so i'm not sure why this is happening with winavi.thanks in advance

 

mo one can help at all?