Vista - suddenly I cannot play some games

I cannot play some games, for example: Gothic 3, Dead Space, Far Cry
see these photos:

Gothic 3:


Dead Space:


But the following games are ok: C&C RA3, Gothic 2, Mount & Blade, UT2004, UT3.

This is my computer:
OS: Vista x64 SP1
Graphics: Radeon HD 2600 XT + Catalyst 9.1 (8.12 tried too)
MB: ASUS P5WD2 Premium
Monitor: LG W2442PA-BF - LCD 24"

It was OK 14 days ago. The only thing what was changed is my new LCD 24'' monitor. But I think, this is not a problem, because I tried to connect my old 19'' CRT monitor and these games are not playable. I tried reinstall catalyst, but nothing has changed.

Sorry for my bad english, I hope you understand.

After this weekend wasted with installing/uninstalling drivers and programs installed last month I find out this problem is only under my user account. If I run these games under admin or another limited account, it is ok. I compared running processes under my and other account, there are no differences, I even tried to kill almost all processes, turn off firewall, antivir, but nothing helped. I wonder what possibly could be wrong with my account? Maybe I will have to switch to other account, because I think I will never find out what's wrong and maybe it is the fastest solution. But if you have any idea what to try, please give me advice.

have you disabled user account control? sometimes that being disabled doesnt give your system authority to do what its supposed to do.

No, it worked 14 days ago, UAC is enabled all the time, I need it, because I work under limited account.

then the resolution is clear, create another account(or ask the main user to) and transfer your documents to your new account folder, then delete your old account, if it works then its ok, its not an unorthodox way of fixing something, many people have fixed problems by doing this.

Yes, I will do it, because trying to find out how to fix it would take 100x more time than just simply create new account and transfer data, but I hope this situation won't repeat... it's strange, it has never happened me before.