You want to downgrade to the older version (the one that you actually like), but you don't have the installation file. Believe me: it happens. Computer crashes, trashed CD-Rs, and other such disasters will definitely get rid of your installation files.
But you can still get the old versions.
If you go to OldVersion.com you can download just about any popular program. They archive several (or more) of the old versions, all of which are available.
The site itself doesn't charge anything, but any registration fees that you would pay for the software (i.e. upgrade from trial to full version) still apply.
And it's not just for antivirus or antispyware programs. You can find IRC clients, IM programs, zipping utilities, etc.
Interesting side note: they even have mIRC 2.1 - a *seriously* old version. (Oh, the sweet nostalgia!)


