Tried to download several widget's yesterday. Something happened, and one of them has said "Installing" for more than 24 hours. "Cancel Download" is greyed out, and I cannot find anywhere else to abort, restart, or reset the widgets. Anyone have a solution other than wiping the phone and starting from scratch? (I don't want the widget that bad, close though...)

Did you try rebooting the device (not wiping it, just turning it off then on again)?

I have cycled the power and also removed the battery.

Try downloading and installing it again.  That might correct the issue.  Once it successfully installs, uninstall it.  I'd also cycle the phone on/off once I got it off just to be on the safe side.

Good luck.

I have no way to download and install it again. it is hung at "Installing." The only option is to "Cancel Download," but that is greyed out and not able to be selected.

I had this same problem on my HTC Hero (Sprint).  I was able to resolve it by going to:

Settings->Applications->Manage Applications->HTC Widget Download Manager

Inside this Application info, I selected "Clear Data" and "Clear Cache"

After doing this, I shutdown the phone, and removed the battery for about 30 seconds.  After replacing the battery and turning it on, the Widget was no longer "installing", and I was able to download it again, and it installed without a problem.

I should also point out that earlier in the day, I had gone into Manage Applications, found the problematic Widget (in my case it was "Dice") and uninstalled it from there.  This did not resolve the problem, and it was only after doing the aforementioned steps was I able to resolve the issue.

I'd swear I looked at everything in manage applications, but I missed that one till tonight. Cleared it, restarted, and reinstated. Everything good now, thank you!

Cool tip!

Can you believe that I did the exact same thing.  I knew it had to be in there somewhere but I completely overlooked that one in the menu.  Thanks again.