It's custom, I built it, and I know what I'm doing. The HD is fine, though I am thinking of moving to an SSD at some point soon just to see if that's going to help the performance of Lightroom (4), so perhaps that will help. The computer is fine in every other way except Lightroom, and the tablet. And the performance of LR4 is a widely-known issue. The tablet issues didn't happen on the other computer because I haven't been able to invest the required amount of time in order to test it thoroughly. I think I was only able to put a few hours of editing into editing on the laptop; I have too much other work to get done that needs to be done on my machine. Besides, other people have this issue as well. Sounds like something with the Windows 7 64-bit driver, and Wacom isn't exactly looking at it.
All do respect, replacing the computer is not an option. I refuse to replace it in order to make a $350 tablet work the way it is designed to work. This is not my issue, or my computer's issue, it's Wacom's. If it was on my end, my system would show other signs of something wrong, and it doesn't.