After installing updates, my Win 7 system will almost always fail to boot correctly. The Win 7 startup animation shows, and then the screen goes black (as it always does, even when it's functioning normally), but then you can hear an extreme whine from something inside the computer (might be CPU or SSD, don't know), and then it will restart. Running the recovery thingie doesn't help. The computer will continue to restart until the changes are reverted/fixed (it seems like booting in safe mode reverts these changes automatically).
Ever since I got Win 7, it has behaved oddly. I'm thinking it might be the SSD - an Intel X25-M, because once I tried installing Win 7 on a standard disk drive, and I did not encounter any problems like this with it (same system, just another drive). The first thing Win 7 did after install on SSD was to crash. 2nd time it managed to boot successfully.
Installing updates one at the time usually will cause less problems. You might not be able to boot Win 7, but usually you can boot safe mode, and the updates will not be reverted, but "configured". And after that's done, you can boot normally. But it's tiresome to do this for every update.
Apart from not being able to install updates normally, the system works just fine.
I might add that not all updates do this. The updates that change Win 7 core/the way win 7 operates are alot more likely to cause failure.