Does the Lenovo update tool you're using look something like the one in this video? If so, you've used it to manually check for updates, installed all it makes available, rebooted, and then repeated those steps until there are no longer any updates being offered after a manual check? Also, the video show an "Additional Updates" button at the 1:12 mark. If the tool you're using has such a button please use it to open the support page for your computer and copy that link here so we can have a look.
Out of curiosity, did your computer originally come installed with Windows 7 64-bit? 32-bit Windows won't be able to make use of physical memory beyond 4GB if the computer actually already has more than 4GB or you decide to upgrade the memory.
If the memory test passes with 0 errors please try using the system to see if the bugchecks continue. If they do, please run the Sysnative collection app and make the new zip available.
