Galaxy Ace won't open WhatsApp because of GooglePlay

[AC Question]

I have a Galaxy Ace GT-S5830. Originally, WhatsApp was working perfectly. Then I received a message saying that my version of this expired (at the end of June, I think) and needed updating.
When I attempted to do this, yes - I got the dreaded "insufficient space" error. So I deleted all unused apps, still no luck. So I deleted WhatsApp and reinstalled it.
According to my Settings (Manage Applications, WhatsApp), it's there loud and clear: Application 28.59MB, Data 8.07MB. But it won't show any received messages because the messages page won't display.
What I get instead is a message to back up with Google Drive. So I select a frequency, choose an account (my gmail) and press to install Google Play PEGI 3.
I accept the things that have to be accessed... and then I get the Insufficient Storage again. So I view that, and it is:
SD Total space 14.14GB, available ditto, internal phone available space 18.54GB.
If I click the WhatsApp icon, I go back to the Google Drive setup screen again. And so on ad infinitum.
Having tried everything since the end of June, I am now just about desperate. Can anyone please advise how I can open the app that appears to be installed? Can I remove whatever is getting in the way?
Many thanks, Alec.

 

[anon(9983233)]

Often we tend to over look the obvious, simply deleting the cache within the apps settings.. or disabling the app. and as a late resort uninstalling the app. if your system is stating that you've run out of space/memory etc.. Then I would explore the system's settings > storage > tap on "Miscellaneous" > select all those which do not have any baring on the system and delete/remove/clear. This should free up some space..

While in this mode/screen select other options like Downloads, Cache data etc,.. and systematically remove all those which have no baring on the system.. You attempting to free up space without deleting any apps. However, this could mean that several apps may need to be adjusted or even shut down. Using an app like Opera Max will help you shut down those apps which are not necessary and limit their usage.