I have a Windows XP Professional x64 virtual machine to run some HLDS processes. I chose the x64 edition as I already have a license for it, and as it uses the Windows Server 2003 kernel it'll be more reliable (and up longer) than Windows XP Professional x86.
The HLDS processes have their game contents updated from our subversion repository, which requires HTTPS transport. We have our own CA for this, and all our certificates use SHA-2 (SHA512) signatures with RSA 4096-bit keys. Sub-version works fine with this right away. I also use a Perl script to periodically check the subversion repository for a new revision every 3 minutes, which also downloads updates if available, and stops/starts the HLDS processes if the update includes server binaries.
The issue is no applications would claim the signature of our SSL certificates are valid. Chrome, IE8, and Perl would all be affected. I found hotfixes KB938397, KB968730, and KB2641690 which apparently fix this, but they have not fully done so. Chrome now works fine with our certificates, but IE8 and Perl are not. Pretty odd that subversion (SlikSVN and TortoiseSVN) are not affected by this.
Other things I've tried is installing our root CA into the local computer's trusted root certificate authorities store, ensuring all Perl modules are updated, and installing OpenSSL.
I'm not too bothered if IE8 never works with these certificates, but I really need Perl to work.
Thanks for reading :)