I've uninstalled, reinstalled, rebooted, and done it all over again.
It won't let me install typically, and when it does, it often errors with "Writing to C:\Program Files\SecondLife\SecondLife.exe"
If I click "Ignore", it goes through the install normally and starts the program. When it gets here, it can't find two DLLs (both with "cg" in their names) and I had to find these manually. Once I did, I put them in the folder and restarted the program. It told me I needed to upgrade to the new version (keep in mind, this is the one I already installed. I downloaded the installer from the web). After this, it keeps doing the same thing.
My system:
AMD Athlon XP 3200+ (2.1 or so GHz)
1024 MB RAM
160GB+80GB Hard Drive
NVidida Geforce FX 5500 from PNY (128MB VRAM)
So, yeah, it should work, but it's not. I was able to play the preview just fine...
Help Linden Labs!