mouse clicks cause XP to freeze and systray icons to vanish

There IS a quick fix to this problem...but the problem keeps recurring. I only have one example, but I intend to keep a list of such instances and the particulars the next 4-5 times it occurs.

OK. Just today I went My Computer and right clicked, in turn, on the C drive and the G drive. C is my master; G is my slave. From the context menu I selected re both drives, "Backup." Both gave me the message: "The 15 day trial period of Acronis True Image has expired." Well, that is correct. (As an aside I now have to pay for Acronis if I want to use it.) All this seems straightforward enough.

NOW, I right click my E drive (my CDROM). There is no 'backup' naturally enough. (I just wanted to see what the congtext mneu held for an CDROM drive.) I now click the F drive (my CD-RW). Immediately I get an hourglass which I can move around but within the window that is ALL I can do.

Well, I get out of this situation by going to the Task Manager and close the relevant program--the CD-RW link I guess.)

And what happens? The monitor loses all shortcuts; the desktop picture remains. In about 15" all desktop shortcugts return, BUT out of a normal 14 systray icons, only 8 plus the Windows clock remain. But everything currently on the monitor works!

How do I correct that? Reboot. Everything is 100% normal.

So...this happens oh maybe once a month. But it's been happening for months on end! I admit a reboot is a quick-and-dirty but effective solution. But what is going on and what can I try to stop it happening.

Other innocent clicks cause the same behavior but as I noted at the start I don't have a list of several such instances at present.