The steam forums will probably answer your question. I would note however that there is a banner on the game's steam page saying that it doesn't work well with Windows 7. However I just reinstalled the game on my Windows 7 laptop and besides a few crashes (which I've tracked down to weather/item mods) its been running fine. However Bethesda games are well known for being temperamental/ buggy as hell unless you play them with very particular setups.
If you have mods, then remove them all. If you don't install the
unofficial patch and the
error corrections mod. Failing that backup your saves, start a new character, then jump to the place that you were receiving the crashes. Its been years since I played the series properly, so those are just non specific crash fixes.
What do you mean by one room at a time? Isn't the Statesmen Hotel just three big cells? Do you mean you're crashing repeatedly within the same cell, or even in the same location, or that it happens when you enter a new cell? I don't recall the super mutants in that location having unique
IDs, so unless you've got a mod that alters them (ie Marts Mutant Mod, FEV, or a weapon mod) I doubt they're the issue. However if you do have mods installed it could be any one of a ton of issues. If you don't have any mods installed and its happening in a number of locations, both within a single cell and multiple ones, then I expect its either a corrupted save (thus the backup your saves and start a new one suggestion) or a software issue I don't know of.