I have Windows Vista on a Toshiba laptop and have been less than pleased many times. It is slow to load, won’t shutdown sometimes, won’t run some software even though it ran on another vista machine just fine and the final straw, my fine new $9 1gb flash drive would not load up! I kept up on updates and some things seemed to get better, then another hang when shutting down. Well I heard that Service Pack1 rc1 was available and I thought, what the heck, maybe it will fix some problems. So I went to get it and what a mess. the first way presented is a registry hack and it failed twice. Then I looked for the IT version, a big download of all parts you may need. It took a bit but I found it. Scroll down and choose the huge 400+mb file.
After you get it on your system just start it up and let go. It will install and reboot about three times. It takes about an hour to run. After it completed I notice a much faster boot up and then hanging shutdown went away. As a test I thought I would try my USB drive again and wow, it loaded right up with no trouble.
It looks like this service pack had some fixed fixes in it. this is supposed to be a roll up package but I think there is more to it. I definitely suggest you install this service pack. It appears to make the systems run faster and more reliable.
Like this post, buy me a soda ($2)