I can't browse certain websites

Hi,

I am on a 2008 aluminum body Macbook running osx 10.9.5, using Chrome mainly. As of yesterday, I have been unable to access certain Google websites (in particular) and the behaviour is as weird as it is excruciatingly frustrating. I can access those websites perfectly fine from other devices (e.g. my android phone). This behaviour persists on both Wi-Fi and Ethernet (only with my macbook).

I can access google.com (and search, so it's not a cached page.) and GMail (I receive new emails just fine). Yesterday I couldn't access any other google pages (support, books, drive, docs, youtube). Even embedded youtube videos wouldn't show up (on facebook, e.g.). Any and all other websites that I normally use load perfectly.

The error I get on Chrome is "This webpage is not available. ERR_CONNECTION_CLOSED" and I get similar errors on other browsers.

Today, for some bizarre reason, YouTube was working briefly (other google sites remained inaccessible) - even loading videos I've never watched before, so it wasn't cached. Now, I can't access YouTube anymore.

Here's what I have tried / noticed so far:

– There is no google-related websites or IP addresses in my hosts file. (In fact, hosts file has never been edited.)

– I have deleted my Network profiles, re-created a profile and Wi-Fi connection, and deleted my network and re-created it and inserted the password manually

– I have reset the router, and restarted my computer.

– All other devices access these sites perfectly fine, and this behaviour persists on my macbook on both Wi-Fi and ethernet.

– I cleaned all caches with Yasu.

– I don't have PeerGuard or similar apps.

– I have no proxies set-up anywhere.

– Nothing strange in my firewall settings, and I haven't changed anything there in months anyway.

– This behaviour persists across browsers (latest versions of Chrome, Firefox, Safari), also other apps (e.g. Google Drive app can't connect.)

– I can ping drive.google.com, for example, and pings normally. However, if I try to traceroute the same address, I only get this: 1 * * * , 2 * * * , 3 * * *. Not sure what's happening there.

– I've disabled firewall entirely, problem persists.
– I CAN access said websites (e.g. youtube, google support) if I use a VPN/proxy (e.g. hide.me) just fine. (Which would imply something is happening with firewall settings?)

– I tried changing my DNS settings to google public DNS (8.8.8.8, and 8.8.4.4) but this is even worse - not even google.com works in this case. (Reverting to my old DNS settings at least I can access google.com, but none of the other google websites.)

– I tried changing DNS settings both at router-level, and on the computer's Ethernet/Wi-Fi connection settings, same result.

Could someone help, please? I don't know what to do anymore. As far as I can tell this started yesterday, and I don't remember doing anything weird or unusual, or it starting after doing a particular action. This is beyond frustrating, as all these sites work perfectly on other devices, except this one.

Thank you in advance - I tried searching the forums (and the net in general) but to no avail so far.