Vista issues from 2gb to 4gb?

I'm sure you grabbed it already, but if you haven't - install KB929777

Besides that, it'll be down to Bios and motherboard. Some don't like driving 4 DIMMS at once. So you may have to bump the voltage a notch, perhaps the FSB a notch as well. Next step would be to loosen timings a bit and *maybe* even downclock. But I'm pretty sure that last one really only counts for modules which are factory overclocked to begin with.

Obviously this will be completely dependent on your individual setup: I have my 1066 stuff downclocked to 800Mhz. I had it as high as 1k, but the voltage needed to do that (2.3) was over the rated. I don't like doing that to RAM... It was stable and I left it there for a while. But with the thought festering in my head for a while I changed my mind about it, set it to 800, tightened the timings back up and declared victory.

Well, have you snapped that stick of Ram in yet? I am waiting curiously. From the looks of your system, I too would add that one stick in the remaining slot that you have. Why wouldn't you? I just added 2GB for a total of 4GB. (3086 MB on my 32 bit system) I couldn't stand the thought after noticing the empty DIMM slots after installing a new graphics card. I would go ahead and install. It only takes about 10 minutes from shutting down, installing, and rebooting.

Let us know what you experience after the install. Seems there's plenty of interest and support if you need to troubleshoot. We got your technology back!