I had a six year old Windows 7 PC running with an uptime of 335 days.
...Then, no joke, it lit on fire. Burned a couple of PCI cards, but the motherboard is still okay!
A moment of silence to your PCI cards.
I don't often put my Windows PC at uptime for more than a week...
Funny this comes up now. I was just cleaning malware off a laptop. I eventually found and did the factory reset, but I decided that I had enough when it still kept crashing hard every 5 minutes into doing something useful.