I have a partial answer to why your desktop icons stop working. Mine do the same - intermittently. Following a tip from another forum, which suggested a connection between Internet Explorer 8 and this problem, I opened Task Manager and discovered 3 instances of the iexplore.exe process, two of which were ghosts from previous IE8 hangs. I closed my IE window and killed the remaining processes, and my desktop became fully functional again.
It seems that this problem is caused when Internet Explorer 8 hangs, which it does for me fairly frequently. When it does, I usually use Task Manager's Applications tab to restart it. Evidently, that sometimes causes IE's window to close and reopen, but leaves a rogue iexplore.exe task running. It's the rogue iexplore.exe task that makes the desktop stop responding.
The remaining questions are: Why does Internet Explorer hang, and why does that cause the desktop icons to become unclickable?
I can begin to provide some more information, but it would be helpful if others who have experienced this problem could jump in with some more. Maybe we can then get to the bottom of this issue.
I'll begin by saying that at least in my case, trying to troubleshoot this in Safe Mode would be a waste of time. The problem is not going to manifest at startup in Safe Mode. For that matter, it doesn't manifest on a regular startup, or even after simply logging out and logging back in.
It may very well be a software conflict of some sort. IE hangs frequently for me, most often while I'm using LogMeIn.com via my Virgin Mobile broadband Internet USB stick. That accounts for over 90% of my IE usage on my Windows 7 computer, so I'm not in a good position to say if it occurs when any one of those things isn't in use. I can also tell you that the hangs occur most frequently when my Virgin Mobile broadband device is getting poor reception. It could be that either the mobile broadband software or IE times out if it waits too long for a reponse from a web site (and remote control sites require a lot of data to be sent back and forth, which increases the opportunity for such timeouts) and hangs.
Or it could be something else. My system setup is not especially complex, but I don't have a whole lot of stuff that I'm willing to uninstall for the purpose of troubleshooting this annoying but minor problem. For example, I use 4 gizmos on my desktop, all of which shipped with Windows 7: calendar, clock, weather and news feed. The latter two require Internet access to update. Incidentally, the gadgets continue to respond even when the desktop icons don't. But if evidence starts pointing to these gadgets, I don't mind turning them off.
However, my computer is a Lenovo ThinkPad, which uses Lenovo's ThinkVantage software. I'm not willing to uninstall those to see if they're causing this problem. I find the ThinkVantage Toolbox to be a handy way to keep my notebook updated with the latest patches and drivers
from Lenovo (and they seem to send out an unusually large number of those), and I want ThinkVantage Access Connections to manage my wireless connections because it does some very helpful stuff when I move from network to network, such as managing default printers and firewall settings, that Windows 7's built-in WiFi tool doesn't do. Could either of these ThinkVantage programs be causing a conflict with IE? Of course they could. But I'm not willing to do without them unless it turns out that almost everybody experiencing this problem is using a ThinkPad and ThinkVantage software.
The other applications installed on my computer are Adobe Shockwave Player, Flash Player, Air, Reader and DreamWeaver CS3, the software for my Canon PIXMA MP500 printer, Diskeeper 2009 Trial (which I'm uninstalling as I type this because the trial expired some time ago and I thought the software had uninstalled itself anyway), InterVideo WinDVD 8, Java v6 Update 21, Microsoft Office Home & Student 2007, Norton Internet Security 2010, Picasa 3, Nitro PrimoPDF, Roxio Creator Small Business Edition (OEM - came with the computer) and Skype. All updates available from Lenovo and Microsoft are installed. Everything else installed is a driver
or utility provided with the system, needed for some component or another to function. My computer has exhibited the IE hang/frozen desktop problem intermittently since I bought it, which probably rules out Dreamweaver and Skype as culprits, since those programs are my only recent additions.
I welcome others to chime in so we can see if we can find the proverbial smoking gun.
Lebowitz IT Services LLC