TF2 Crashes very soon after connecting to a server

My PC is more than capable of running TF2 on the highest settings, and yet it often crashes almost immediately after connecting to a server. Either it'll crash on the Message of the Day page, before selecting a class, or it'll last about 60 seconds and then crash. Other times TF2 will run fine.

Has anyone else been having this problem? Did you fix it?

I'll give that a go, thanks. I also think that it might be depending on the server I connect to, but I'm not sure.