Im having trouble with my wifi. I replaced my router and now every time I boot my computer from sleep, the wifi freezes and there is an exclamation mark in the icon for wifi. I have to then turn off my wifi and turn it back on by right clicking turn off/on. I went into network preferences> advanced and deleted the old router from the preferred networks list, but this did not fix the problem. I also have checked and unchecked remember networks this computer has joined and that doesnt fix the problem. Im on a core i7 late 2013 macbook 13 with yosemite. Yosemite has all the updates so far. I dont know what else I can do and Im kind of stuck. Your help would be much appreciated, thank you.