Recently, I've been experiencing some glitches with the game.

Basically, I've had Heroes 5 and all its parts installed on my computer for a very long time. I would occasionally play them because I don't have much time. But recently, I had a week off and decided to play the campaign. Everything seemed fine, but some strange graphical glitches started appearing, like stripes on the screen, and sometimes the whole screen would turn an odd color. When I rotated the camera and tried to focus on these stripes, the screen would start flickering, etc. I'm not very knowledgeable about hardware or anything like that, but it seems like it's either a problem with the driver, DirectX, or something else, but I'm sure it wasn't like this before! And when I decided to play a single-player map, it got even worse. The computer would just freeze after a battle or simply fail to load the save file. I've already reinstalled Heroes, DirectX, and the drivers. I downloaded DirectX from the official ATI Radeon website, where I also found the drivers for the video card. I even tried installing older drivers for the video card, but it still didn't help. :((
Maybe there's already a patch that fixes this for me now... Tribes of the East, version 3.0.
If anyone knows the reason, please let me know.
Thank you in advance. :)