I'm glad we were able to help you figure out where the problem lies.
When I saw you come on earlier and didn't post, I wasn't sure if it was a good sign or a bad sign, I guess that answers my question!
You can play around with mmview to see if disabling any other Video codecs and leaving those will allow it to work without crashing, but if you want to use DVD Complete it won't hurt anything to disable the codecs when you need to access then from Explorer if you want to do it that way.
Prior to running HJT the first time, there were a number of programs I installed to check for viruses and malware. Some of these I guess have no expiration but others have expired like Spybot and Ewido anti-malware. Do you recommend that I buy any of these programs to keep on my computer? If so, which ones do you recommend that I buy?
SpyBot is free and doesn't expire and it's one we usually recommened. After the 2 week trial, Ewido goes to the free version which can still be updated and run so I would keep it (but really no reason to buy it since you have the real-time protection from Windows Defender and SpyBot). You can uninstall Trojan Hunter and SpySweeper since they are both only trials and I recommend Ad-Aware
if you don't already have it. I would also definitely keep your Zonealarm firewall.
As far as purchasing any programs, that's completely up to you. I personally use SpySweeper and Ewido and for anti-virus I use Nod32, but the programs above will work great without having to purchase anything (you'll just have to manually update Ewido periodically and run it).
You are very welcome!