why u have ur automated w7 updater on??? there is NO support for w7 from MS. after getting those needed one (like 200-300 of them) there is no need for auto updater cz MS dont support w7 anymore.
i would check latest updates and in order remove them on by one and check on after every removed if it works. also check latest scheduled tasks if there is any new ones before this issue started.
clock does not do that without an issue by itself. btw on pirate version of w7 clock should work just fine its other issue than there is and more likely some useless update that does not work with programs or tasks that is making this. 99,9% sure this is not clock issue. some update more likely.
updater can also be reason of this cz it can now be left running on loop and can only be shut down by closing and disabling it then shutting pc. then open pc, open clock settings and check internet time and "check now" now ur pc is running in right time but if u shut ur pc without battery u may have to check it when reopened. i hope this works for u.