I have the exact same problem.  I am actually on this site now looking to see if anyone else is having similar problems.  It crashes when buying clothing, either during or after.  Crashing using temporal mod and everytime you summon more than one person.  This is only since installing Seasons and BV, right before had a party and summoned about 75 to 80 sims to the party with everything up to Pets in game.  Now, crashing on sim number two.  With my computer, it's not a computer problem, not a graphics card problem in any way, it's not a paging file problem, or a RAM issue, 4g of ram.  Anyway, just started with Seasons and BV - not sure whether to uninstall, don't even want to play without using summoner and temporal mods.

Go into your game files,
my documents
 the sims 2
delete the file "Groups.cache" and it should load.  You may have to delete this file everytime you try to open bodyshop.  My game wont' even load until I delete that file. Don't worry, game will regenerate the file.

It's one of two things, computer is overheating, motherboard overheats or graphics card gets too hot or the power supply is getting interrupted.  I had this problem so frequently, and it was clear mine was a power supply issue due to living in post Katrina New Orleans with a temporary power line hooked up for us right now.  But, I had a rough three months of my game crashing, the whole computer crashing only when I played my game.  The computer went to a black screen and had to be manually powered off and restarted only to have it happen again, soon, once the game was up.  I was restarting my game, sometimes 6 times a day due to crashes.  I purchased a power supply regulator and it solved the problem.  My game is huge, I have an Alienware computer two years old with a seriously sweet motherboard, excellent $650 ATI graphics card, extra fans inside, don't even have to run the cooling system that came with my computer, so it was a power problem.  Try a regulator, get it from somewhere you can take it back if it doesn't solve the problem, but your problem sounds exactly like what I was experiencing.  I play with a power grid that sucks, and the power regulator keeps it from crashing and going to the black screen where all you can do is power off.  The power regulator I got was around $200, but they have them cheaper, mine was worth every penny, couldn't even create a sim without it crashing the computer.

Hi, I've read through every post, and can't find anything exactly the same as what I need to know.  I might have downloaded the wrong version, but after reading all this -I'm thoroughly confused.  I have been using this mod, but only with YA's at home, for the age group only, didn't care about going to college from home.  But, I went to play with my college today, and there are no college options for the actual college students.  Then, they all aged to adults.  I aged them back using insim, but they changed right back to adults.
here's what I need help with
1- I want to play with the college students on campus, going to class and not turning to adults
2- I would like to have ya's at any house off campus too, anyway I can get them other than messing up my college students on campus

What version and additional downloads do I need?  thanks