My install of Vista which is about four weeks old due to new hardware, does not thrash the hard drive. I have loads of data, about a terrabyte of stuff over three hard drives. I have not disabled anything and only notice a lot of disk activity if Outlook is open. I guess its indexing my emails. I have found over the past 8 months of Vista RTM, drive thrashing occurs when there is something wrong. It could be memory related, I found when I had a dodgy stick of ram, vista had to keep loading all the time. I even got a few BSODs and other random crashes though. My guess is you have a driver that Vista is not happy with or some software installed it doesnt like. I could be way off here, but thats my experience. I do leave my PC on 24/7 so perhaps its caused because you are booting up often?