Question Laptop Network connection drops access to the web randomly (except for Google Search, Youtube and Gmail)

I hope someone can help.

Recently my Laptop began limiting my access to the majority of websites randomly. I would try to search something using google's search engine in which I would get results, however; when I click on any of the search results I get an on screen message that says "This site can't be reached" "www.(anysite).com's DNS server could not be reached." Now this response occurs with every website -- except when accessing google.com, youtube.com or any other Google affiliate website. So far the only way I have been able to correct this issue is to restart my computer each time this occurs. Of course several hours after I restart my computer this issues will surface again. I am pretty computer savvy but I have not been able to find a fix for this issue. I have adjusted the settings of my DNS (in the Network Sharing section of my computer, under the TCP/IPv4 with no avail). Every forum I have found with someone else dealing with the same issue, does not really get resolved. I have had this laptop for 6 years now, with no issues. I am trying to understand why this issue can only be resolved if I restart my computer each time? PLEASE HELP! I am running Window 7, I have Bitdefender 2019 installed, and I also use express VPN from time to time. When this problem shows up, it does not matter which browser I use (Chrome, Firefox, Tor etc..) as the same message is displayed. Other than that my computer is very basic...I don't have much installed on the PC, so I am trying to understand why this is happening and what restarting the computer does to fix the issue temporarily? IF ANYONE has a permanent solution or fix for this issue, I would greatly appreciate your input. The next option for me if I cannot fix this issue will be to wipe the drive and start over. Thank you to anyone who can provide any insight. If you have any questions for me...feel free to ask.