It's funny to install windows updates if you have a somewhat slow (in modern terms) computer. Go get a torrented Windows 7 with updates rolled in till a few monthes ago. Install Windows.. with the custom stuff (updates + script that installs IE and .Net) it takes about two hours to install.
Then it takes about an hour to boot, reboot, install Firefox (downloaded with ftp.exe), change wallpaper etc., install some shit and an AV (this is a single core low power PC with 1GB and old HDD)
Then it takes a shit lot of time to find Windows updates. Two days later, it's still not finding them!
I give up. PC's getting a pain to use, I go for upgrading it to 1.5GB or 2GB. cool, turns out I've plugged a 2GB module in, it now has 3GB. The PC still is miserable but has a lot of ram just like my everyday beast!
Wait.. Now the fucking "windows updates" software that was stuck at "checking for updates" now finds updates (about 63 of them). WTF? (I had tried some .bat file found on the net to "unstuck" it, but dunno if the RAM ugprade did something or it wanted just one more reboot..)
So, in conclusion (tl;dr) there's some dark ugly voodoo that determines if Windows Updates will actually work. If it does, it's of course extremely CPU and memory intensive : if you have 1GB RAM or perhaps even 2GB RAM (which runs very low if you use programs) the PC could be so much fucking slow at installing updates that you run the risk of getting infected. I mean, two days of running Windows with unpatched old zero-days and what not! It makes me feels really dirty. Also, it's self evident that Windows 7 is about as bad as Vista on resources use.
But it was not like that time with XP + IE6 where I got obviously infected before I was even done setting it up.
Not sure if the Windows 7 PC is infected or not. Got to 98% memory use and swap hell with only windows (indexing etc. disabled), avast and firefox running (and task manager) ; firefox was only taking less than 20%. Had to kill firefox and disable the antivirus (killing firefox through task manager didn't go so well : not working, and "firefox is not responding" message not coming because of swap hell. Firefox got killed just when I had opened a command prompt which would have served me to kill it)
Got enough RAM to run, you guess it.. Windows Update! I installed that one critical update available and rebooted.