ATTENTION MMD AND MODEL MAKERS. I NEED MUCH HELP.

Why do I get the feeling that you posted this in the wrong place...?

And why do I get the feeling that you're still in your deviantART phase...?

Adlez, no need to be derogatory. Her spelling is correct, and she isn't using chat speak - I think she's fine. People use all caps and exaggerated words here all the time. :/
And this is the correct place, don't worry.

I don't actually know anything about MMD, so sorry if this post got you excited about help, but I just wanted to clear up any confusion/worry from Adlez's post.

Perhaps the model has far too many physics and/or unneeded vertices. I've had that same problem before, except it was just crashing MMD, rather than essentially freezing it.

I would put my bet on the issue being alot of bodies/physicsboxes and whatnot overlaping form the clothes and the base. When using a mmd base the first thing to do is see if it has any leftover bodies and joints, and remove them. The Same applies to clothing. I've seen some people putting upp clothes and bases that still had hair and skirt bodies, so allways keep it in the back of you mind to check, even if it says its clean. Its easier to remove those things when you dont have alot allredy there. Ofc you can delete them one by one on the physics section of pmd/pmx, but I prefer box select.