1) Start menu or taskbar icons not working after some time
Most definitely NOT fixed. The root cause of this issue appears to be registry mishandling during user logon (probably a windows bug). I have done a lot of research into this issue (see my replies to http://www.bleepingcomputer.com/forums/t/608833/automatic-update-caused-your-start-menu-isnt-working/page-3#entry3992276 ), however I have not yet been able to capture a process monitor trace of the mishandling occurring, and so have been unable to complete my analysis.
I have to diasgree with Rocky Bennett in that it is an isolated issue (in fact I believe that the underlying bug is extremely widespread), however I believe that in most cases, the affected users do not recognise that they ave been hit by this issue. In many cases the issues experienced are not Start Menu malfunctions, and additionally Windows can in many cases silently fix itself on next logon. An example of other failiure symptoms can be system tray icon order/visibilty temorarily changed, or loss of settings in apps, sundry software experiencing issues (oftern fixed by a 'reboot' [logoff/logonon actually]).
Some software (Dropbox is one example) sets registry permissions that happen to prevent the "silent fix on next logon". This in NOT a bug in dropbox, it is Microsoft's dodgy sticking-plaster repair routine. In this case, the issue is much more likely to progress so the start menu critcal error which does not repair on logoff/logon/"event 1542 on logon" state, or to become non-trivial to repair.
If "hit" the best thing to do seems to be to recognise it immediately, and to log off/on. I have a scheduled task that runs at user logon which setects that the issue has occured and warns me. I can then log off/on immediatelty to let the cleanup routine do its work. I also uninstalled dropbox (with it installed the repair is much more convoluted than a simple logoff/on).
If "hit", the worst thing to do is to carry on using the same logon session - The 'corruption' stemming from the registry mishandling will become increasingly more critical the longer that the faulty logon session is used.
Is the issue still present? - Absolutely - the most recent time that I was hit was yesterday (a couple of days after the receiving the latest updates). I It ied to be hit on maybe 2% of logons.. I have sen the issue on multiple systems. It is a major reason for me vetoing deployment of Windows 10 at my workplace.
If you are able, you could take a system image of your current system, to the ugrade to gain the digital entitlement for your W10 on hardware, then restore your old OS image until you are ready to move to 10.