Yes, running a single antivirus is generally preferable and many antivirus programs will fail to install if another antivirus is on the machine.. Besides, since two "realtime" antivirus programs can frequently conflict with each other, it's not a real good idea to have two installed.. If you're wanting to use AVG, you'll need to remove Bit-Defender at least.
So, try uninstalling Bit-Defender first.. It should allow AVG to install..
The other items, Ad-Aware, Spybot, and SuperAntispyware are antispyware programs and don't run "realtime". Still, Spybot and Ad-Aware have been causing a few problems with program conflicts lately.
This senior Newbie started downloading the AVG 8.5 from Cnet to my PC running winXP and suddenly a window opened that said basically, conflicting antivirus software is running on my computer that would cause problems with my computer if I contiue, it said to delete the other programs.
I quit the installation ommediately.
I have Adware, Spybot, bit defender, and Super Anti Spyware on my computer. Does this mean that I cannot use AVG Anti-Virus 8.5, unless I delete these other programs from my computer??? Sounds weird. thx for any help. Swellmel