F4LL0UT: I had the same problems a while ago (earlier this year). Only the Google services were affected and only in FireFox. I think the culprit was some other software that connectied to the internet. I think I always got these issues after launching the Battle.net client and haven't run into those ever since I've stopped using that client. Really weird stuff.
Cyraxpt: Actually i recently updated the LoL client after a few months without playing it but not sure how it would also affect the other laptop that doesn't even have any games installed.
shadowrgog: I use Firefox too, but if that were to happen to me, I would uninstall ALL my add-ons and firefox too and start from a clean slate. (First re-installing only Firefox then slowly add-ons). Basically it's the good old 'turn it off and turn it back on again' approach (a running joke from the show the IT crowd). If you tried that already, then I have no idea what could be happening other than maybe virus scanning the system or installing an older version of Firefox and if that fails, well you know what to do...good luck figuring it out.
Cyraxpt: Eh, i want to avoid doing that since it would block my Steam market for a week. Besides, wouldn't FF safe mode work if that was the case? I also doubt it's virus since i keep my laptop well protected and i don't interact with the other laptop so it would be weird both laptops having the same virus.
I'm more inclined to believe it's router related, that piece of garbage always gave me problems with having to open ports and stuff...
Right, well routers aren't my strong suit so I can't help out with that so good luck. Reinstalling stuff could be a pain, I know it varies with the person's lifestyle regarding how they use their browser. Safe mode seems legitament, but as you mentioned it didn't help so I offered a more...radical approach I guess. Safe mode would have been my go to of course since it disables extensions and stuff but if it's a deeper problem in the browser, I personally wouldn't know what to do other than start over, of course keeping things like bookmarks and stuff in a seperate area to reapply later. Anyway, I hope you get it sorted it out eventually, since you seem pretty busy with other ongoing things like your Steam market.
Edit:
Cyraxpt: Btw, gog is also having problems but i assume that's due to the sale/free game, right? Or is it only me?
I get increased load time (due ot the constantly changing tickers and deals) but nothing else. Any orders I make on gog and web viewing work fine with me anyway (using Firefox).