I just installed the blender 2.55, and whenever I try opening it it crashes immediately! I can’t even get into blender 2.53 anymore because that crashes also! 
Anyone else have that problem or know how to fix it?
I had this problem and I solved it by uninstalling Quicktime. I have no idea why that would cause a problem, but it did. The person who gave me this solution re-installed Quicktime and it still worked on their computer. When I re-installed Quicktime, it started crashing again. Hope that helps.
I don’t even know if I have QT… as far as I know I don’t, but I never had that problem until now after I installed 2.55! I uninstalled blender I’m going to try reinstalling it and hopefully that helps… 2.49 still worked so maybe there’s a conflict with having 2 of the 2.5x’s installed?
I uninstalled it and reinstalled it and it did fix it… but this time I clicked on the 32 bit instead of the 64 bit like I did last time, but I do have a 64 bit… It did say something about not having quicktime and some other support with the 64 bit so I’m not sure what that was all about… but anyway I was able to get it working.
yeah, I had exactly the same problem. 32-bit worked fine, but 64-bit crashed on start every time. I’ve been running several different versions of Blender for a while and never had any problems. You just have to make sure that they are each in their own Blender folder. There’s another thing that I remember hearing. Be sure you have the latest C++ redistributable. I really don’t know how to find it, but I know you can DL it from Microsoft’s website. Glad the 32-bit worked. Hope you get 64-bit working too.