Your FireFox memory seems a little bit high, probably because you are visiting pages with Flash content.
Curious, in Task Manager how many CPUs does your CPU Usage History show?
Windows Explorer is not the same as Internet Explorer... Win Explorer is Windows File Manager and the Start Button and Desktop - don't worry about that one.
I totally suspect your slowness to be caused by a networking issue.
Make sure you have the latest drivers for your WiFi adapter.
NETSTAT -es at a command prompt will show you if you are getting a lot of network errors.
You can disable the Xfinity Guest SSID by visiting your My Account page.
You should be using either your own WiFi or the Xfinity password protected SSID, not both.
If your router is a newer one that offers dual band (2.5 & 5 GHz) then I would see about disabling the Comcast one and using your own. If not, consider using only the Xfinity access point and removing your completely.
I would suggest getting a free utility like InSSIDer 3 from MetaGeek to see what WiFi channels are currently occupied.
I suspect that everything is running on Channel 6, and that is the root cause of the slowness (shared radio frequency bandwidth).
If you have lots of neighbors, keep your SSID at the most unused channels.
You want to isolate to the least used frequencies. If you notice a lot of slowness when Netflix is being used, try to hard wire your streaming clients to reserve the WiFi signal bandwidth.
Another option is to use Netflix on the Xfinity SSID and use your own router's SSID for your stuff, as long as they are on very different channels.. like 3 and 11.
You can always try to connect your laptop directly to the router via a wired connection and disable your WiFi on the laptop... that would give you a quick hint of it is your WiFi signal or not.
On the other issues.... Always backup data. Always scan for Malware and Viruses. Always check, defrag and optimize your hard drives if they are more than 10% fragmented. Always monitor neighboring WiFi channels to keep your SSID at the best performing frequency.
Hope this helps. And don't be shy about asking more questions... there are a lot of smart people on this forum that are very willing to assist!
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