How can I view old Demos?

[Soundwave]

I recorded a few demos from various Steam games last year, HL2 Deathmatch, CZ, CS Source, TFC and then forgot about them until recently. Of course now they won't play in-game, I assume because of the updates since they were recorded. So I was wondering what I can do to view these again. I'm almost certain there are programs or workarounds to be able to view these old demos but I don't know any specifics and I would really appreciate if someone could help me on this. Any info is appreciated.

 

[Beerdude26]

Old demos have the tendency to crash randomly. I'm not aware of any workaround, I'm afraid .

 

[Soundwave]

These don't so much as crash as refuse to play at all. The farthest I've got with any is the TFC ones, which will play for about less than a second and then it crashes as well. I would also like to add that I got an old demo in Counter-Strike Steam version playing just fine, but none of my own do. So there's got to be a way to get these working.