HP helps. It tells me you probably have way too many things running in the background while you are trying to play. Hit Ctrl-Alt-Del and click on the Processes tab. If you have more than say 25 or so running, you are probably going to have problems. Maybe not, but its a good bet.
Once you start Aces High, and the first clipboard comes up where you tell it to go Online or Offline, click on Video Setup. What is your Max Texture size? If it's at 1024, turn it down for sure. I'd put it at 256 for now, you can always increase it later if you get your comp stable. You certainly dont want it over 512. Also, look to make sure you arent preloading anything into memory, and dont allow it to download skins in the background. Close Aces High.
Right click on your desktop, select Properties. When the window pops up, select the tab on the far right, Settings. Click the button on the lower right that says Advanced. The top right tab of the new window should be your video card, Geforce 7800. A window will also pop out to the left. On it, select Performance and Quality Settings. To the right, in the middle of the window, find the setting Antialiasing and set it to Application Preference. Do the same for Anisotropic Filtering. Vertical Sync should be ON. Image Settings should be at High Performance. Hit the Apply button and close out those windows with OK.
Restart Aces High and see if you have those problems. Assuming everything is good, you can start increasing eye candy settings until you notice a performance hit. Find the best balance for you.
If there is no help here, Click on the Start button, select Run and type dxdiag into the dialog box. Hit Enter. When the Direct X diagnostic program starts, run the tests for video and sound and go to the last tab. There is an option to save a copy of the report. Do so, save it to your desktop where it's easy to find. Open it, highlight all the text and copy it. Then write an email to Skuzzy at
support@hitechcreations.com and paste the dxdiagnostic info into the email. You may have driver issues that need addressing, Skuzzy can help you with it.
Good luck.