Couple problems all at once...im going crazy

K so originally when i recieved my new computer 2 weeks ago, I went through 3 days of troubleshooting between charter and dell, which ended with them blaming each other for the problem with the modem, until finally dell realized it was a bad integrated network card, so they sent me a new motherboard. Someone came out and installed it and got it working. Then the modem started cutting out so I had someone from charter come out and redo all the lines outside cuz they said the signal was cutting out bad before it even reached the modem. Now 4 days later another problem has arose, my dads computer which is using wireless says theres a line disconnected between the laptop and the router. First theres no line, its wireless...and secondly it just happened out of the blue for no reason which makes no sense either after it worked perfectly. Oh and about 2 hours ago my computer lost internet too for a few minutes and then came back on. But i've tried doing all the regular troubleshooting stuff I can think of and nothing seems to be working, did all the unplugging and replugging stuff too. Does anyone know why it would say theres a cable disconnected? And as a side question, I set up the wireless and it says I can disconnect the cable but when I yank it out of the ethernet I don't get internet. So I have a wireless router and wireless on my desktop but I can't get the wireless working without the ethernet.....im confused and my head hurts now, if anyone can help please lemme know what to do. If you need anymore info to figure out the problem please ask ill be happy to tell ya whatever.