I keep getting a white square in the bottom L/H corner there is a icon next to the safely remove hardware icon which says get windows 10.I think the white square is connected to that icon.My OS is Windows 7
If it is the Install icon as opposed to the Win 10 availability icon, then note all the posts about updating Win 10 and consider as to the problems that others are currently experiencing. Albeit there are those who have successfully installed without problems.
Do not jump to do it, there is no need to rush into it.
If it says GET Win 10 then it is asking if you want to reserve your copy of Win 10 and will advise you as and when it is ready for you to download.
Some have done this and downloaded and installed successfully BUT there are many who are experiencing a great number of problems. If in doubt do not at this time, wait till all the dust has settled and all the problems are sorted.