I got told I had viruses

[Taistelumestari Viiksi]

It's me here again, yay!

Okay, here is the deal. My old computer had been crashing few months back, so I sent it to warranty repair, it being package computer and all. They told me that the motherboard was broken and they changed it, np, no more bluescreens or weird errors. Since then I have bought new computer (in parts this time!), and gave the old one to local company for office use. They ran some tests of their own and reported to me that the computer was infested with viruses of some sort, and that was the reason for the crashes. What boggles me here is that I never ever had any viruses on the computer before or after repair, at least according to weekly full scans with Malwarebytes and Avast, both of them. I never encountered any suspicious slowdowns either.

So I am asking here, what are the odds having a computer infested with viruses and Avast OR Malwarebytes not detecting it, and not suffering from any slowdowns?

[Deleted]

If you only use MBAM/Avast there's a chance, however the "big" virusses should be picked up by both.

What makes them think it's a virus? What OS are you running? Also, is it x86 (32-bit) or x64 (64 bit?)

- Logicaly

[Taistelumestari Viiksi]

Old computer had Vista 32 bit.

Edit: Don't know what makes them think it's a virus / viruses, gotta call 'em later today.

[Deleted]

I'd give Combofix a try, post the log here

Make sure you follow the guide exactly, and disable the AV/Firewall/All other scanners before starting it. Also, save it first on your Desktop and Right click it --> start as administrator.

- Logicaly

Edit: link to Combofix: http://www.bleepingcomputer.com/comb...o-use-combofix

[Taistelumestari Viiksi]

gave the old one to local company for office use

I don't have that old computer anymore which supposedly had those viruses, was just asking for gut feelings :<

Edit: off to work now ->

[Deleted]

Ah well to your original question then: There is a small possibility it has a rootkit or botnet running, they usually run as a low-priority process so you don't notice them. However I somehow doubt small companies & computer security... They're usually wrong