Antivirus - Screen conflict

Each time I run Comodo Antivirus, my desctop would be scrambled. Fonts of icons, headings of windows are changing, sometimes are blanked out. I use Firefox. All the text disappears from Firefox window, from the actual pages, and it is impossible refresh it with reloading the page. I suspect some kind conflict with the video driver software, I use 5500 with the correct driver software.
I changed from AVG to CAV at last Firewall update becausue of the conflict between AVG and CIS, but I could never run a full scan jet since change because I could never see what happens, so I had always restart Windows after running CAV for some time.

Can you please post your specs?
Your Memory Size, CPU, OS etc etc
Example: 256MB 1.1Ghz WinXP Pro Sp2

Does the scrambling only occur while running a scan?

Jake

CPU : Intel Pentium 4, 1700 MHz (17 x 100) (P68 Willamette) without overdrive (1700 MHz Clock)
Memory: 1024 MB (PC3200 DDR SDRAM)
Video: nVIDIA GeForce FX 5500 without overdrive 270MHz GPU
Logical (Windows) HDD:
C: (NTFS) 81917 MB
D: (NTFS) 157065 MB
E: (NTFS) 77830 MB
F: (NTFS) 78724 MB

OS: MS Windows XP PRO SP3
Virtual memory: 3485 MB
DirectX: 4.09.00.0904 (DirectX 9.0c)
.NET 3.0.6920.4016 built by: GDR
Desktop:
1024 x 768 x 32 bit
Font 96 dpi
Vertical sync 70 Hz

Yes, I have not experienced it earlier, and not other times, only when I run cav.

Thank you.
fabijoe

When I read the symptoms my first thought is graphics driver problem. Does the problem happen when you install a previous version of the NVIDIA drivers?

I think, it was due to spywares yesterday I killed off from my system. Thank you for your efforts.

fabijoe

Is there any other issues that are still present?

Jake

No, thak you. I was fighting some rough rootkits on with malwarebytes tech assisancy, and got some spywares killed also. Since then everything seems to work as normal.