If memtest still shows "No errors" after a few hours of running, then your memory is most likely fine. However, if hex digits, etc. have been shown in the area at the bottom, then this usually means that one or more RAM modules are bad. The memtest never ends, so if it hasn't given a problem with the length you've run it for, then it's safe to assume the RAM is fine.
Probably the best and quickest test for the RAM is to remove all but one RAM module and run the setup CD. If it gives a BSOD, remove this RAM module and try another. If you get another BSOD, then the RAM is likely fine as the chances of having two faulty RAM modules is very slim. However, if the Windows setup works fine with just the one RAM module installed, then a RAM module removed is the culprit.
It's also worth checking the BIOS and try changing the AHCI / SATA settings. For example, try setting them to legacy / IDE mode (or disabled for AHCI) to see if the Windows setup CD works this time. If it does, then the OS CD (or nLite customised) does not support your SATA controller in native mode. Just be warned that if you install Windows with AHCI disabled or SATA running in legacy mode, you'll not be able to install the SATA drivers in Windows or change the modes back in the BIOS, as the SATA drivers need to be installed during Windows installation. There are a few hacks going around on how to use SATA drivers after Windows installation, but these only work with some SATA controllers.