Well, here are a few more pennies, just for giggles:P

Your AV software is probably working like crazy to analyze all those new files you are pouring onto that hard disk. It could be erroring out because of the load, or causing a conflict with one of the other applications. Zone Alarm might actually be interfering with it's ability to figure out what a PZ3 file is or something.

I recommend adding your runtimes as safe folders in your antivirus programs. It's highly unlikely that a virus will target them, and you should be scanning anything prior to installation- so it's a reasonable option. It will also speed up load time for your favorite items, since your antivirus program doesn't have to first scan the file before poser gets it.

Sounds to me like you found the problem. Just to be sure, though, I would run something really hard on that machine for hours. Make sure to fill up the ram and work the processor for a few hours. If you have vue or bryce, render something really complicated. If not, I'm sure you can coax poser into overextending itself and working for hours on a render:P Just make sure it's maxed out and stays busy for a couple of hours. If it bluescreens or restarts during that, you probably have a hardware problem that only showed up when you worked the machine really hard (by scanning tons of files for viruses). If it survives it, you probably did have a software problem.

Good luck:)

eric