avast! Free Edition doesn't work

[Voelyn]

Do not install more than 1 AV.
I don't like AVG at all, I know a lot of ppl that had many problems. The only ones I tested and were good were Comodo and Avira AV only. I use Comodo without AV and Avira free AV.

I was a fan of AVG for many years, then i switch to Avira. Although AVG is good at detect malware but it use a lot of CPU and Physical memories till sometimes it make my Laptop freeze and need to restart! Eventhough it(AVG) is a user-friendly antivirus but i choose Avira for now. Avira use less CPU & physical memories, and my laptop run smoothly...

* And please don't install more than one AV as they will clash with each other.
Cheers!!

[krabuzh]

thank you for all the advice
I am using avira free now, and yup it runs smoothly
it seems that there is a certain virus on my comp that made all the AV I installed didn't work
though I don't know what kind of virus is that

[Munemasa Katagiri]

It might be a false positive, it's the only con I see about Avira, a larger number of false positives. Upload the file to VirusTotal - Free Online Virus, Malware and URL Scanner

[gollumsfriend]

I also heard you're not supposed to have multiple AV programs in use at the same time...they have too many conflicts with each other (avast and avg together, etc).

I tried AVG for couple months, didn't feel safe with it---I never had proof it was actually doing anything. Never tried Avira before.

Glad you have things running smoothly again!

[gokunaruto]

On the contrary I had only positive experiences with AVG. The new 2011 version (10.0) just came out and looks very efficient. Scan is optimized with a new "user-sensitive" option which doesn't overload your PC.

I was using Avira too, and this is a good choice, but it was kinda slow on my PC so I've changed. Don't know about Comodo, never tryed it.

Of course don't install more than 1 AV .

[SpiritOfTheWinds]

Do not install more than 1 AV.

Well I did that over 2-3 years ago when I got badly infected (not a simple virus, I got a few hundred of them that installed themselves hidden into the windows folder). Not one of these were good enought to permanently remove it, but when they were together, the removal went so smooth. I never had problems after that. Thought that was the only time I used 2 AV... Antivirus are never perfect, free AV or not.

Just get the one you're happy with.

[onmyouji]

You might have a virus which is preventing the antivirus from working properly. Also, when you uninstall Avast or almost any other app, it is good if you clean registries etc. before installing it again. If this doesn't help, try different AV. I always recommend COMODO being a freeware combination of Firewall and AV, but tbh COMODO runs good only on a fresh system and by someone who can be bothered with a more paranoid AV.

[noone]

well, this is now a week old and you said you're using a new AV, but if you still haven't gotten rid of the virus, you could try doing it the old fashioned way

i'm assuming you're using a windows of some kind - not sure the AVs you mentioned are working the same way on mac or linux or other systems. but we're all lazy so most of us stick to windows lol.

if you have access to a clean computer you should use that to get the tools you need before using them on your own computer. if not, use safe mode with networking on your own computer (it will allow you access to the basic parts of the system, but hopefully prevent the virus from acting up and doing whatever it's doing.)

get into safe mode / safe mode with networking (when the computer boots, you hit the f8 key before the windows logo comes on screen - if it does, you weren't fast enough and have to try again.)
once you're in safe mode, install and update the latest version of malwarebytes' antimalware soft, the run it. let it do a complete scan and after it finishes it, you'll have a list of possible infections in your computer. you can quarantine them or delete them - i'd advise you just select "remove threats" and be done with it.
after it does this, restart your computer and let it go to normal boot. if there are no bads with it, re-install mbam and run it again (it's my experience this can't be installed or work properly in normal log on in an infected computer, so if there's any suspicion, you have to do it in safe mode first and only then you can install it in normal mode.)
there might be some more detected threats - just select "remove" and if it asks, restart the computer.

just in case, you should install an AV on a clean system. so you might re-download and re-install the kit for your favorite AV, after removing the present one and cleaning the registries, just to be safe.

make sure all definitions are up to date and schedule an all-scan at boot time once in a while, you never know what might come up.

as other members have already said, you shouldn't have more than an AV working at any one time, but make sure your firewall is up and up to date. don't allow many exceptions to it, and those only if particularly needed.

if you browse a lot, there are tools to keep you from getting another problem - like addblock for firefox, and whatnot.

tools:
malwarebytes' (the free version is more than enough):
Malwarebytes' Anti-Malware: Malwarebytes

ccleaner (to clean up space and the registry files):
CCleaner - Optimization and Cleaning - Free Download

as for avast, i've been using the free version for years (4.8 and the 5, lately), with no major problems, and a very few of the small problems (what avast didn't stop, mbam cleaned after easily - mostly suspicious cookies.)
(the free version doesn't catch everything, but it's sufficient enough to protect a normal-use computer. if you use it for e-banking or more sensitive affairs, you should pay for a complete protection AV.)

[krabuzh]

@onmyouji: thank you for the advice! I'm cleaned the registry

@noone: yes you are right! It seems that my lack of knowledge caused all of this..
I've downloaded the CCleaner and found out that there are so many 'things; that need to be clean/fixed from there.
Now I know why my comp refused to run any AV beside that I also found a virus in it.
Didn't know before that you also have to clean your comp every time you uninstalled or deleted something

Thank you once again for everything!