Okay let's try some standard things.
1) Rename the AVI folder to AVI_back
2) Set the color depth to 16BIT
3) Turn off everything in the background like E-mail/ICQ/Messenger, Virus protection and everything in the system tray beside the clock.
4) Update your Windows, update your Video card drivers and audio card drivers. Then repeat steps 1-3.
Especially turn off Norton, that thing causes many more problems than it helps.
1) Rename the AVI folder to AVI_back
2) Set the color depth to 16BIT
3) Turn off everything in the background like E-mail/ICQ/Messenger, Virus protection and everything in the system tray beside the clock.
4) Update your Windows, update your Video card drivers and audio card drivers. Then repeat steps 1-3.
Especially turn off Norton, that thing causes many more problems than it helps.