Outlook in VM not responding - want to bring window to front All,

Every once in awhile, when I click on a window in MS' Outlook 2010 to bring it to the front, it doesn't respond. Sometimes, I see the outline of the window I want to bring to the front, but it doesn't jump to the front to make it active/functioning. My set up is Windows 7 32 bit, running in Parallels 8 with 2.5 gigs of memory and 2 CPU's.

Any thoughts?
My set up is Windows 8, Parallels 8 2Gb and 2 CPU, Outlook 2013.

I used to have these "not responding" messages in Outlook 2010/2013. From activity monitor I can see a lot of background activities of Avira anti virus program. I'm tired of all these "not responding" messages. Finally today, I uninstall Avira, and suddenly Outlook 2013 profile loading is a snap. Processing also a snap..
No more not responding.

Prior to removing Avira, I checked its log file and in there it reported numerous times on trying to scan Outlook's each OST files or pst files whenever I accessed them. Those outlook mail data files I really need to have them together in my Outlook folder panes..everytime, hours a day, and referred to numerous times a day. My email data files are gigs large.. 

I guess, will have to find another anti virus software with less cpu/resource loads..

Hope this can assist you.