Hardware problem? or other…….

When I plug our dedicated analog phone line into the RJ11 connector on my laptop, it literally disables the phone line and I cannot connect to the internet. The dial tone remains cut off until I disengage it entirely from my pc. If I do not, it will not reset itself and my husband would be unable to get a dial tone for his own laptop. It has always worked before, but has been into the repair shop recently for other unrelated repairs…….

Please, any thoughts?