So you have two issues.
I think I can help with Explorer crashing and for your Windows Update error 80073701 you need to tell us what the update KB number and/or description is that is generating that error. Personally I am tired of figuring out Windows update problems so maybe somebody else will help with that or depending on what the forum moderators think it might be best to have a new topic for that issue and keep this one to your Explorer problem.
What is your system make and model?
Describe your antivirus/antimalware environment (Norton, McAfee, etc.).
When Windows Explorer (not Internet Explorer) misbehaves or cashes on a right click the cause is usually an afflicted shell extension.
Shell extensions make up the list of options you see when you right click something in Explorer.
I will post some instructions for how to troubleshoot an afflicted shell extension.
Included in the first part are symptoms of a problem mostly with Acer systems that come preinstalled with MyWinLocker from EgisTec. That problem showed up after a Windows security update a couple months ago but you have not said if your system is an Acer, something else or home made.
If you mean you are seeing something like this:
If that is the case, read this:
Perhaps you have an afflicted Explorer Shell Extension.
Explorer Extensions make up the list/menu of things you see when you right click something.
An afflicted Explorer Shell extension can cause Explorer to crash - especially when using copy/paste and/or drag/drop and often to/from an external USB attached drive or device.
Several recent incidents involving Acer systems and MyWinLocker from EgisTec (which is already known to include some troublesome Explorer shell extensions) which may have come preinstalled on your system.
Even if your system is not from Acer it may have MyWinLocker installed and since there have been many reports of it contributing to Explorer crashes it seems a good place to start looking.
If you look in your Installed Programs and find MyWinLocker or anything from EgisTec and you don't know what it is or why it is there consider just uninstalling it, rebooting and then see how things work. You can always reinstall it again later if needed, right?
If you have determined that MyWinLocker or any other EgisTec programs are involved follow the general purpose instructions below so you will be able to see all the Explorer shell extensions and figure out which one is afflicted.
After using The following program suggestion if you see any extensions from EgisTec, PSD Security Software, eDataSecurity, DragDropProtect (they will be some of the pink extensions) start with those first.
If none of those things are present, continue:
When Windows Explorer (not Internet Explorer) is misbehaving (especially when right clicking), start to suspect third party Explorer extension add-ons. You may also see Data Execution Prevention (DEP) errors. DEP errors are reported when Windows feels threatened by a program and Windows will shut down the threatening program. Windows should never feel threatened by Windows Explorer (or Internet Explorer) unless some add-on is the cause.
Those would be Explorer extensions that do not belong to Microsoft. That means extensions that you added. Explorer extensions are usually okay and installing some applications will install Explorer extensions for you, give you a choice and sometimes they can be added without your knowledge when you install new software.
Explorer extensions are sometimes added as a new right click option you see on folders and files (like scan this file, open this file, play this song).
If there is a particular thing you do when Exploring that you know will cause the problem, that will help zero in on the problem and help you know for sure when you have found and fixed it.
If you can make it happen anytime you want, make an adjustment and then there is no message the next time you do whatever it is you do, you have found and fixed it.
First you need a way to see what Explorer add-ons you have installed now and a way to disable them (not uninstall them) so you can figure out which one is causing the problem. You may have lots of non Microsoft extensions installed you don't even know about.
Download ShellExView from here to see which Explorer extensions you have loaded:
ShellExView doesn't install anything on your computer, it just runs and displays.
After you launch ShellExView (double click shexview.exe) and acknowledge the security warning, adjust the column widths so you can see everything clearly. Under Options, choose to "Mark Non-Microsoft Extensions" and the non Microsoft extensions will be in light pink, but on some systems that is a hard color to see, so click View, Choose Columns and move up or move down the Microsoft column so it is closer to the top (Move Up) so you can see it on your screen without having to scroll left and right.
Next, click the column header called Microsoft (it may be way out on the right side of the screen) to sort the display (by clicking the Microsoft column header) so all the non Microsoft extensions are at the top and easy to see. They will say "No" and be marked in pink since they are not Microsoft extensions, something like this:
The non Microsoft extensions would be things you have added (non Microsoft) and are what you need to be suspecting.
If you see extensions that do not have anything listed under Description, Product Name, Version, Company or have peculiar names that looks like they might be just random numbers and letters, you might want to look at those first.
You can also Google the name of a suspicious add-on and see if there are any hits regarding Explorer crashes or DEP errors and what other people have done about it.
You might Google something like:
<my-suspicious-add-on> windows explorer crashing
You have to fill in the name of your suspicious add on.
See what kind of search results hits you get and look for solutions or situations that sound like yours.
I am not a trial and error advocate, but I can't think of another way to do this...
Right click and disable the non Microsoft extensions one at a time (or perhaps in little groups of 3-5) keeping a list so you can enable them again later if desired. The result of the change is immediate and no reboot is required. Test your (right click) failure condition. If Explorer starts to act normally, you will know that some extension you just disabled in that group of 3-5 is the culprit so you can start to enable them one at a time until explorer fails again.
One user reported that there was a need to restart Explorer after each adjustment so to do that press Ctrl-E from within ShellExView.
If you recognize any extensions that may have been added or downloaded recently, start with those first.
Disabling an extension does not uninstall the extension - it is just disabled. You can always enable it again later, so keep track of things by writing them down.
Disable them one at a time or in little groups (to make things go faster) until your right click does not generate an error, then reboot and test again to be sure. That last extension you disabled would be the suspicious one.
You can also just disable all the non Microsoft extensions, reboot, test your failure condition and enable them one at a time until you find the one that generates the failure condition.
If you have a lot of extensions, you could disable them is little groups, 3-5 at a time instead of 1 at a time until your system starts to behave.
When it does behave, you will know that the problem is one of the extensions in that little group and you can enable those in the group one at a time until the problem comes back, then the problem will be with the last extension you enabled.
The hope is that you will find the one extension that causes the problem and then you can figure out what to do about it - either uninstall it or see if you can get an update from the maker of the extension from their web page.
I don't have your issue but I can when you disable/enable the extensions, the extension is immediately disabled, so disabling an extension does not seem to require a reboot but if you think you found the problem, I would reboot and retest anyway to really be sure the problem is gone.
If you post up a list of your non Microsoft extensions, maybe someone will recognize it as a potential problem.
If you find the offending extension that is the problem, please let us know what it is so I can add it to my list!