While this is not a consistent problem (that is, it might happen once every three full moons), I noticed that the executable VProSvc.exe had been slowing down the system not by using the CPU but rather by consuming all available physical RAM. It was forcing disk r/w operations to virtual memory so that other applications could keep up. The Task Manager showed it was using nearly 50% of physical RAM (>850,000 KB RAM). The only solution was a system restart. And in fact, as applications were shutting down, VProSvc.exe was even adding more memory to >900,000 KB and >1,000,000 KB during shutdown. It was probably even delaying shutdown, although Windows eventually did shut down (after 10-15 minutes!!)
On restart, I could see VProSvc.exe taking up far less, from 1000-3000 KB usually, and up to 30,000 KB if a Norton AV window was open.
What would make VProSvc.exe "race" to eat up memory like that in the occasional Windows sessions? Is the only solution to do a system restart?
Machine: HP Pavilion dv9500t CTO / Intel Core 2 Duo / 2.0 GHz / 2.0 GB RAM
OS: MS Windows 6.0 (Vista Home Premium 32-bit) SP2
Installed Norton products
1) Norton Ghost 15.0.1.36526
2) Norton Antivirus 18.6.0.29