Hi, BurtW
I suggest that the alert message is a result of ISBmgr tool (ISBmgr is a battery checking utility). So try to mount a hard disk image using Parallels Mounter and then rename isbmgr.exe (it's location typically C:\Program Files\sony\isb utility) to something like isbmgr.ex_. After renaming, the tool will not be able to start up. As result the alert message will not be shown at next boot.
If my suggestion is not correct, I need to know, does OS allow you to run programs, browse your disk after alert message was shown? The session terminates only after you press OK in alert window?
What version of Parallels Desktop do you use?
WBR,
Stuw