As you can see from the title of this post, I'm having trouble finding the right programs for my troubles. I'm quite new to mapping with Valve engines and also new to The Whole Half-Life, so I am sorry if there are things that are already on this website. I am trying to decompile a certain map from the original Half-Life, c1a0b, because I'm going to make a fan made expansion pack with another friend. I've tried things such as BSP2Map, and it works.. Except when I test it in Half-Life, all the textures are in weird forms, and it's very laggy, until I reach the next map, it all goes back to normal, due to I think it loading up the next map. I've been googling, slightly going on the Valve Developer Community, and other things.