Windows 7: Problem with USB drives (icons)

I've been using Windows 7 for nearly a year. My internal drive houses Drive C: while I use an external USB drive, partitioned into D:, E: and F:. Most of my apps are installed onto C: or E:

Very occasionally, the whole USB drive fails to get detected at boot-up. The first symptom I usually notice is that any shortcuts to the apps on E: (on my desktop or my Taskbar) get replaced with the standard one that Windows assigns when it can't find the actual executable. So instead of seeing my usual icons, every app has the same boring icon. This is particularly troublesome on the Taskbar because I can't tell which app is which!

To make matters worse, whenever this happens, Windows 7 seems to replace those icons permanently. Even if I reboot later with the drive online (or switch it off and then on again) those icons never come back again. Refreshing my desktop using F5 doesn't seem to help either. In fact, the only way I've found to get them back is to install some new software.

Can anyone suggest a way to refresh my desktop icons without needing to re-install software all the time?

Next time that you have the problem, note the time
Go to search
type event viewer
Look for all the critical errors that occured at that time.

Thanks Richard but I strongly suspect that the error will simply be that the drive didn't wake up (maybe it was in sleep mode or something). I'm not too concerned about the drive as I can easily switch it through a power-up cycle. I'm more concerned about getting my icons back.

Some further information.... in 'My Computer' I can see the drive OK and all it's contents (once it's back on line) but the desktop and taskbar icons seem to be lost forever. I've even tried deleting my desktop shortcuts and unpinning my taskbar items, then setting everything back up again but even that doesn't work. So far, the only solution I've managed to find is to install some new software, which is very inconvenient.

[Edit...] I had an idea. Put the relevant icons somewhere on my C: drive then point my shortcuts to the icons. Since they're on my C: drive I should be able to see them, even if the E: drive goes offline occasionally. This is simple to do for a desktop shortcut (because you can specifically set its icon) but I can't find a way to do this for a Taskbar item. Any ideas??