Heya, newbie here.
I’ve been using Avast for a long time, but lately I’ve been seeing some unusual things with my computer, mostly having to do with shutdown/restart issues.
I’ve been thinking about using AVG to double-check for viruses, on the off-chance that AVAST missed something.
Is it safe to run AVG and AVAST at the same time, or will the two AVs conflict? ???
Welcome to the forums,
I dont recommend use 2 antivirus at the same time in your machine. No matter if both are active or not. Avs usually installs a lot of stuff in your computer and change settings, wich may cause some conflict.
If you wish to have a second opinion, you may go to http://www.trendmicro.com or us.mcafee.com and use the online scanner. It can be installed without problem no matter if you have a full package antivirus installed or not. Both are only demmand scanner, exactly what you need to get a second opinion.
Thanks for your time,
Elminster
try some online scans from rejzor’s site to be sure 
Listen to the others but, if you want the exactly answer, it’s yes, you can have avast (resident) and AVG (not resident) running at the same machine (XP SP2). But, please, look your steps: you’re doing a ‘dangerous’ thing that you must know what you’re doing. Take care of both email scanners at the same time. They work togheter but you must know how to configure them…
I’ll recomend BitDefender (free) or AntiVir (free) as a second, non-resident, scanner.