@Veridis Quo: Jack is the GM and the final word here. I am just general commenter/organizer/human notebook; didn't notice anything objectionable from my skimming of your CS myself (else I'd have commented it). Jack's been rather preoccupied, if his somewhat scarce, laconic and formal replies are any indication... I'm sure he'll reply you once he has a moment to concentrate on your CS.

@Jack: Router/networkside issues have been ruled out. It is something your computer handles strangely. MSE and whatever comes with Win 7 Home Edition shouldn't be a problem, either. (Admittedly, I myself nuked the default protection my own Win 7 Ultimate had, as it both demanded fair bit of resources and, well, Win's default protection is *bad* and can't even detect half of the things while overreacting to others. The Win 8 I have still has its original protection, I think ... mostly because I've never really used the thing for other than checking whether something runs or can be made run natively on Win 8 every now and then; it simply came with a laptop given to me, I installed a second operating system onto it almost right away, and then mostly forgot about it. The last Windows I used somewhat more excessively was Win XP Professional. I was also offered a free copy of early-access Win 10, but at the present date I don't actually have it on any of my devices.) 
As for antivirus/firewall in general, then eh, I've seen plenty of computers which are filled with enough ticks, trackers and other critters (depends what places you go to - some sites are more notorious for spreading malware/adware/spyware/trashware than others) for those alone to slow a computer to a crawl[1], so sometimes running something significantly more potent than MSE and clearing those out can be useful. (Installing Malwarebytes' trial version when people start to suspect something might have settled in, fixing what is broken, and then removing it again seems to be a rather popular thing to do.)
[1]Being a person who has a long history of keeping an unreasonable amount of programs running at all times and never switching computers off, I tend to get fairly sceptical when people say a handful background programs slow their computer down. Although often computers get slow just because they are filled with dust... If you make something that semi-consistently pulls air in from one end, you essentially get a miniature vacuum cleaner.
Eh, I'll see whether I get any good ideas in regards to session management, else trying through random options it is. Right now I need sleep and to finish this one thing I am working on (in terms of actual work ... volunteering? in any case they pay me ... also things that are actually confidential).

Edit: Since this thing confused my punctuation for formatting. Again.