Precision 5560 often turns on with no wifi and hang on during restart (blue screen appears

Hello,

I am having a very big problem with my laptop - probably wireless network card. From about 1 month approximately when I turn on my laptop, there is even no wifi icon in Windows (all the wifi options disappear and I don't have Internet access). My wifi card in the device manager can be seen as turned on. However, the device manager freezes when I try to turn the wifi card off. My computer says the drivers are the newest ones.

Even worse, when the wifi problem appears, the computer hangs on during restart / shutting down. So, every time I have the aforementioned issue, I have to hard reset my laptop or wait till there will be a blue screen after few minutes with information that there was a problem with my system. I have tried to troubleshoot the "internet problems" with Dell Support Assist, but it is "attempting to resolve my problem" for more than "few moments" with no results... When the computer happily turns on with wireless network card available and I have an internet access, but I am e.g., switching to different network - the wifi disappears too and cannot be normally restarted / turned on... 

I have a feeling that lastly the issue is more frequent (appears for about 50% turns on).  I don't know if the wireless card is physically damaged (hardware problem) or it is only a software problem. However, the times that it turns on normally, all the troubleshooters (Windows / Dell) say that everything is working fine.

Please, help me