Hi, I have used DS free version several years. When I installed the 2018 version, it worked well several weeks, but then suddenly started to crash every time i select one option of draw or modify. First it freezes the computer for several minutes and finally appears following message: First window: Draftsight alert (dont respond). Second window: Microsoft windows, program don't respond. Do you want to close the prosess Y/N. I have tried to reinstal the program several times without any success. What can I do?