I'm in the Temple of Elemental Evil on the second floor fighting with the Fire Troop Commander. In the battle, after my party member hit him, the battle just stalled and I can't do anything at all. I had to ctrl+alt+del to force the game closed.

I launched the game again and this time went on to fight with the Fire Temple Bugbear. Same thing happened!! Basically I can't continue this game since fighting is inevitable.

These are the bugs of ToEE. Co8 might fix it.

There's a button to enter combat mode (it's been a while since I played, but I think it's space or enter). Sometimes when I hit combat glitches, it helps to enter combat mode, then walk into the combat zone.

Otherwise, an alternative save may work.

If that doesn't work, try redownloading and reinstalling the game (keep your old saves). It's crazy, but that's fixed a glitch for me once (the glitch was that I could only open chests or loot the dead while in combat mode)

I hope that helps some.

If you are playing vanilla ToEE, then obviously you have stumbled on one of the serious bugs that plagued this game. The Co8 mod did fix a lot of bugs, but screen freeze in the Fire Temple and Fire Node as well as the Lightning Trap on lvl 4 is still a recognized persistent problem. Read "The Co8 Guide to Successful Gaming with ToEE" and the section "Known Issues / Hanging Combat" here. It seems to have something to do with fire damage or the fire animations.

Further things they recommend are to not move the screen around too much in those areas. Also, never save your game while in combat mode, as this can often corrupt the save file. Never use speed save either for the same reason.

You might try using ranged attacks or spells that kill from a distance, or luring the bad guys out of the temple or charm them, so they can't do fire damage or those animations are off-screen during the battle.

SPOILER ALERT: You don't actually have to complete any of the temple quests on lvl 2 to complete the game. They just add flavor by opening up alternative story quest arcs where you are given the option to eventually meet the arch-bad-guy sooner and join him (you will eventually meet him anyways if you just keep exploring deeper).

Uninstall, re-install doesn't work.

Installed the Co8 but it looks like playing with this makes all my saved game unavailable from the load game screen. I guess I have to play from the start again.

Unfortunately, yes.

I'm at the same place (Fire Commander). The battle still stuck.

Then read my spoiler alert posted above.

Seems the problem also happen when fighting Vrock and Balor.

Well I found a solution to the hanging battle problem. Summon monster to keep them busy and attack with offensive spells. =)

Thanks for posting these comments folks; I'd been stuck on the Fire Node with the game hanging every time I fought the big Balor Demon thing. I'll have to get back to this and see what weapon I was using. I might get through this game yet! :D

EDIT

Okay I've gone back to that fight and it was the Scather sword that was triggered the crash. Thanks for the link, Dreamteam67!

Unfortunately, my fighter's other weapons are nowhere near as effective against large burny demons from hell! So this might take a few goes to win...

Here's another spoiler for anyone who keeps getting stuck when fighting the Balor in the Fire Node:

SPOILER
You don't need to kill the Balor to get its fire gem. An invisible character with high enough skill can pickpocket the gem instead. An invisible character can also leave through the portal (non-combat mode) behind the Balor while the Balor is still alive, and the entire party will return to Temple level 4.