Windows 7 won't Install Important Updates

For some time Windows 7 has stopped installing important Windows Updates - The 2 Updates failing about monthly are "Security Update for Windows 7 for x64-based Systems (KB[Number])" and "Security Monthly Quality Rollup for Windows 7 for x64-based Systems (KB[Number])". I have just been hiding these updates, but since they're Security Updates, it'd probably be better installing them, also it gets really annoying to always hide them and that you can't see the Windows Update timer when playing a fullscreen game.


When installing updates Windows shuts down, the normal windows update messages appear, but then when starting up again the installing updates percentage goes up to 12% - 13% and then it says "[Can't remember what it says before, if the information is needed, I'll check] Reverting updates" and then restarts again. This repeats until I hide the updates.


When I go to "Control Panel > Windows Updates > System and Security > Windows Update History > View update history" it says that the updates are pending (because I haven't hidden the latest ones yet) and beneath that, that they failed (obviously). For both updates it says "Error details: Code 80070490"


I've had this problem for a while now, so any help and even a solution would be very welcome.


Thanks in advance,

Lorenz