Turning On mouse trails can fix it.
I found that turning on Mouse trails can fix this problem. I have a Compaq V3000 w/ 2gig ram and Vista Home Premium. I just upgraded the other day from XP Home.
I actually had the same problem w/ the pointer on my HP Entertainment PC running MCE '05 that I have hooked up to my plasma in the living room. Turning on cursor trails fixed the issue. However I just upgraded this as well to Vista Home Premium and I haven't had any issues.
It's a wierd and annoying issue, however it goes to show that I'm very happy Microsoft has still included ways to navigate through a modern GUI simply using arrow keys, enter, and the tab key!