Scientific Software International (ssicentral.com) was the vendor for LISREL and PRELIS software, but has recently been acquired by another company. The sales model now appears to be principally that of annual lease via a program called SSI LIVE. LISREL is slated for inclusion in this, but as of today, is not yet available.
For answers today on how to acquire, you'll need to contact [email protected]
Do note that freely available R libraries which ably cover many aspects of SEM modeling (e.g., lavaan, sem) offer much utility and continue to be improved, and are not limited to windows OS.
I agree with David. Of course I don't want to push you in any direction, but I am a former long-experienced LISREL user and I can highly recommend using the lavaan package. Life is hard anyway--there is no need to make it unnecessarily hard in addition :)