I'm still on EasyPHP 3.1, which is similar to the new 5.3, and I run EasyPHP as Administrator on Windows 7. To do that permanently, right click the shortcut in the start menu -> Properties -> Shortcut -> Advanced... -> Run as administrator.
5.2.10 and 5.3 work fine with my windows 7 install. Only slight problem was a parse error displayed on the admin console for EasyPHP.ini on line 13. This also scrambled the labels in the admin console.
Resolution:
change
OldRunningPath=C:\Program Files (x86)\EasyPHP5.2.10\
to
OldRunningPath="C:\Program Files (x86)\EasyPHP5.2.10\"