Botnet, trojan and other undetectable malware in my USB flash drive

Around seven months ago my computer became infected by trojans, viruses, botnets and undetectable malware. I decided to reformat it, so I took backup using my external usb harddrive. The problem is that I think my usb external harddrive is infected now.

Because of this, I am worried to plug it into my computer again because I don’t want to get reinfected, the botnet especially frightens me.

I am lost and worried. I need to be 100% sure that the computer won’t be reinfected.

What can I do? What is there to do (except for running Avast - it won’t help much with undetectable malware though)

OS: Windows 7 64-bit

Thanks

Panda USB Vaccine - Antimalware and Vaccine for USB devices
http://www.pandasecurity.com/homeusers/downloads/usbvaccine/

and scan it with a bunch of tools…
you already have avast
then you may try some or all of these…
Malwarebytes http://www.malwarebytes.org/
Superantispyware http://www.superantispyware.com/
Dr.WebCureIt http://www.freedrweb.com/cureit/?lng=en
how to use DrWeb http://www.freedrweb.com/cureit/how_it_works/?lng=en
Norman malware cleaner http://www.norman.com/downloads/malware_cleaner/en-us

you may post scan logs here if anything is found

What is the USB Panda Vaccine? Why do I need it and can I not do it manually? (Without downloading applications I don’t know what they do? Bad experience with Panda too)

I will scan it with a bunch of apps. Thanks. If you have any other ideas regarding on-demand scanners I accept them.

I think something called Autorun I have to worry about, correct? Anything else?

I think something called Autorun I have to worry about, correct?
yes, and that is what Panda USB vaccine will help you with it is all explained on the Panda website

The recommendation that you install this program.

MCShield

It will prevent infection by computer via USB flash drive, mobile phone or any memory card.
And not only will prevent infection, but will immediately clean Memory card or external HDD

Thanks for your replies.

There is a problem though and that is I am kinda worried to install apps I haven’t seen before or heard much about. Especially worried about destroying the computer.

So two things:

  1. Is in not possible to do what USB Panda Vaccine does manually? Is it a regedit edit? Or a setting change?

  2. Any other tip besides fighting autorun.inf. What about other things?

1) Is in not possible to do what USB Panda Vaccine does manually? Is it a regedit edit? Or a setting change?
This is a very useful tool as there is no simple way of disabling the AutoRun feature in Windows. This provides users with a simple way of disabling this feature, offering a high degree of protection against infections from removable drives and devices.

Worms use several methods to insert the system.

One method is the autorun.inf but there are other methods.

Panda USB vaccine will prevent the autorun.inf method only but not other ways.

MCS uses other methods, He cleanses the USB drive. There is no way that the worm passes by MCShield.

The program was developed a year ago in a Serbia where is mostly used, so it is unknown.

The creator program dr_Bora (antimalware fighter - teacher), is a contributor Gmer, sUBs…

One team member Bobby(antimalware fighter - teacher), is the creator of Malzilla http://malzilla.sourceforge.net/

It’s therefore MCShield a very serious program, try it and see for himself.

Hi

Thanks for your replies

What are your opinion about me using a Linux Live CD instead?

Pros and cons?

Thanks