Why does a restart always solve problems where no reasonable explanation exists... -.-

Probably some bug in memory, when you restart it clears the memory.

Same thing about slowness overtime , it swaps the memory into hard drive and it slows down the performance, don't know how to clear swap in windows, but on Linux sometimes I clear swap and it just works :)

It was about network-visibility. Reconnect did not work, renew / release IP did not work, but after the reboot it worked...

Sometimes its just magic xD

sometimes due to state corruption in memory

"Have you tried turning it off an on again?"