Alright so I searched around and I haven't found anyone else having the same issue.

Last night I came back to replay NWN1 Diamond Edition only to find it crashing on startup. After doing some searching here at the forums, the only fix that worked for me was renaming the base .exe to NWN1.exe. That fixed it but now two weird things happen.

The first issue is my wizard apparently has amnesia, he randomly forgets spells he's memorized entirely so after resting I sometimes have to re-assign everything all over again. He always forgets 1 slot in Level 1, 1 slot in Level 2, 2 slots in Level 3, and 1 slot in Level 5 and it's always the last things on the list.

The second problem I'm having is the game doesn't freeze, but it no longer responds to any of my control and I can confirm it's not me having accidentally paused the game. A weird console command prompt at the top of the screen comes up and no matter what I push or type in I can't get control back and have to alt+f4. I've tried pushing ~ but it does nothing.

Any ideas? The game was working perfectly fine months ago, guess since I haven't played it in awhile my wizard cursed my game out of spite.

Sounds to me you have some INT boosting item (or some other item giving extra spells) you occasionally unequip.
Thus losing the extra slots and forgetting the spells, re-equipping gives you the slots back but not the spells.

When the command console pops up the game no longer responds.
The key combo to call/uncall the console is not tilde for me, can't remember what it is.

About the spells.

The easiest solution is the INT buff. (fox cunning?)
It will be canceled when resting and if you rebuff before looking at your spells you see empty slots.

Ah right, forgot buffing Int would add more spell slots. I suppose me and my wizard have a lot in common now, hah. It's been a very long time! I haven't really messed with my gear though, is my eyeball familiar casting an int buff on me or something?

I'll pay more attention, forgetting spells frustrates me to the point where I'd rather not have my int buffed at all so I'll start being aware. I'll try googling what the key combo is for enabling/disabling the console.

Thanks for the advice Jarmo and Mad3 :)

I like to use items to boost INT and use the extra slots for long-term buffs (such as Bull's Strength, etc). Equip the items, fill the slots, rest, then cast the long term spells. Remove the items (thus losing the now-spent slots) and equip other items of more utility when adventuring. Win/win. The only drawback is you have to remember what spells you put in those slots, and keep refilling them when you re-equip the item(s), but that's not a big deal.

That's a good idea, I'll be sure to use that if I'm in need of some free buffs.

Anyway I found a way to disable the console by editing something in the .ini, so hopefully that'll fix my second issue. Thanks again everyone :)