Another article from Microsoft states that when you uninstall dot net security hot fix, the version of the dll may not roll back to the lst version when you initially install. So don’t have high expectations on Microsoft regarding hot fixes.
http://support.microsoft.com/kb/939160/
I found this below article quite useful which totally describes my experience facing when the Infra Guy update the dot net framework and the website is broken
With all of the .NET patches, Adobe patches, and Sun Java patches that have just been released, it's enough to make one yell "Uncle."
A single PC might need as many as three different patches for Microsoft .NET, so let me advise you on how to handle them.
MS07-040 (931212, 928367, 930494, 928366, 933854, 929729, 928365, 929916)
Multiple patches confuse .NET Framework situation
Our first truly critical patch this week, which I want you to install as soon as possible, is a patch — or, I should say, patches — for Microsoft's .NET (pronounced "dot net").
.NET Framework is a programming run-time environment that's relied upon by programmers to build applications. It's used by and included with such major programs as QuickBooks.
You'll very likely find that you have not one but two (and sometimes three versions) of .NET Framework on your systems.
.NET 1.0, .NET 1.1, and .NET 2.0 all need patching this week. A later version, .NET 3.0, does not need patching.
The Knowledge Base numbers you'll see that relate to this week's .NET security bulletin, MS07-040, include all of the following:
• 931212, 928367, 930494, 928366, 933854, 929729, 928365, and 929916.
The large number of KB articles related to this bulletin is due to all the different versions of .NET and all of the platforms that it can be installed on. It's confusing, to say the least!
You could need up to three different .NET patches on a system, if you have .NET 1.0, 1.1 and 2.0 installed, for example. One server in my company has two .NET versions and thus needed both 928365 and 933854.
Unfortunately, as with previous .NET upgrades, these patches are never easy to get onto your system successfully. Folks in the Windows Update newsgroup are already reporting issues with the installation of these patches.
If you experience any problems after installing a .NET update, be prepared to take the following actions:
• Remove and reinstall the offending .NET version, as recommended by Microsoft in KB article 923100.
• Follow the recommendations to troubleshoot .NET installation issues, as described in KB 824643.
• If you uninstall MS07-040, be prepared to follow KB 934711 for the issues that may occur after uninstalling. You may even need to use the clean-up tool referred to in KB 939160 to straighten out the mess caused by the uninstallation.
As someone joked in the Windows Update newsgroup, it nearly makes you think that a bad .NET install is Microsoft's way to get us to buy new computers running Vista!
However, Vista isn't perfect, either. If you uninstall — and then attempt to manually reinstall — .NET 1.0 or .NET 1.1 patches on Vista workstations, be prepared to need the instructions in KB 934712.
Also, be aware that you'll get a warning message from User Account Control when you install or reinstall a patch.
If you have any issues getting these .NET patches installed, please let me know via the Windows Secrets contact page. Also, be sure to call Microsoft product support at 1-866-PC-SAFETY in the U.S. and Canada, or your local Microsoft subsidiary elsewhere, and complain about the situation.
Most people are having few, if any, problems getting these things installed — but I'd recommend that you have those phone numbers handy, just in case.
Downloading updates causes unhelpful error messages
I learned a lesson this month: when evaluating patches, never use a test machine that's also a PC you use to beta-test various software.
I ran Microsoft Update to try out this week's patches. Instead of downloads, I got a very cryptic error code. I entered it into the search box that Microsoft Update offered up to help me — 0x8024D007 — but no information came back in return.
Google was somewhat helpful, offering up a KB article that lists all the cryptic error numbers, remarkably making their definitions even more cryptic: 928208.
Fortunately, a page on the Tek-tips site finally gave me a clue that a beta product I was testing was interfering and causing the errors. It was easy enough to get that pre-release program reconfigured. But it reminded me how hard it is to debug error messages when we update our machines.
The helpful LangaList newsletter, which merged last year with Windows Secrets, was assisting folks to understand these error codes as far back as May 2003. This kind of gobbledegook translation is still needed by all of us patchers today. Years later, the best troubleshooting tool we have for solving install errors in Windows Update and Microsoft Update isn't Microsoft.com but Google.com. Sigh.
Source of Information:
http://72.14.235.104/search?q=cache:-sbDFgnl40oJ:windowssecrets.com/2007/07/12/06-You-need-a-road-map-to-install-.NET-patches+kb+933854&hl=en&ct=clnk&cd=15&gl=sg