PS CS5 suddenly slows down

[Sapiento]

I don't know what it's doing. But I made an automatic windows update a day or two before this happened so I guess it changed something. Whatever. I turned if of - problem gone.
I will check this 'system internals, Redrobes, thanks for the hint.

[SchildConstruct]

What I am betting is that its looking for new files saved and checking them off on a database on the internet for whether its a pirated copy of some vid. Its probably doing some kind of fingerprinting hash on your file.

It isn't, and it doesn't. It's a service that makes it easier for others to discover the media you share on a LAN. If Windows had such a fingerprinting service, legions of corporate customers would present their astronomical ISP bills to MS.

Just sniff the network traffic your machine produces, and check where the traffic is going.