I can't see that updates could possibly cause you RAM issues and cause your computer not to boot, RAM is handled by the memory controller on your i7 chip and by the bios on your motherboard, neither of which can be in any way touched by updates; the processor has no writeable memory and the bios is effectively a seperate OS that doesn't get updated unless you specifically download a bios update from the manufacturer, it will never be updated by windows update.
I think the more likely answer lies with either a) the type of RAM you're using, b) the bios version you're running, c) a faulty motherboard or d) a faulty processor. I think it's unlikely to be faulty RAM unless you've overclocked the cpu or memory since replacing it, as it sounds like you've had issues since before this current set. If you have overclocked this computer I recommend setting the clock back to factory to see if it's more stable.
a) i7 setups have very specific requirements for RAM, usually you have to buy a set of 3 identical ones with the same voltage to fill one bank to get the most out of your system. If you buy the wrong voltage RAM (i7 requires low voltage RAM, 1.25 or lower), or RAM with the wrong timings, you will probably see a lot of errors. However seeing as you've built it with 3 dimms I think you probably knew this and have purchased the right RAM.
b) Sometimes manufacturers release updates to the BIOS rom on your motherboard due to unforeseen issues (such as memory compatibility). Check your manufacturers website for any updates available for BIOS and perform updates if their are any. Be very careful with this though and, if possible, install the bios update in diagnostic mode (available in msconfig) as if a bios is flashed wrong you can brick your motherboard. It may also be worth clearing the CMOS memory on the motherboard, sometimes if you fiddle a lot with motherboard settings it can store some pretty weird settings that don't show in the bios UI and can cause stability settings, as a test I'd suggest going in to settings and restoring factory bios settings.
c) Many of the early i7 boards were unreliable due to the fact i7 was a brand new architecture, many people had issues with certain boards and were forced to do RMAs or refunds and alternative replacements. Have a google for your motherboard model number to see if anyone had the same issues.
d) The i7 was the first intel processor to include a memory controller on-chip, so RAM issues can now be linked to the processor as well as the motherboard. Unfortunately it's very tricky to give a solid diagnosis of CPU issues such as this, the only way being a RAM check and that isn't foolproof for intermittent memory controller issues.
Also, just in case I've missed something, could you please explain exactly what you mean by won't boot? Does it get any further than the post screen, does it try to load windows but fail, or do you just have a black screen?
And finally, on a side note, bear in mind that the i7 and corresponding motherboards are not designed to be used as servers, even though they are perfectly capable. Realistically the only difference between xeons and i7s are the quality of the fab; the best of the bunch get stamped xeon and the rest are i7, but it's something to bear in mind.