do u need 2 dowload something for a trojan horse to go on ur computer?

Answer 1

If i understand you correct so is the answer yes.
Or you can get it true email.
If you open links or attachments.

Your computer that is online all the time download and uplode all the time.

Try a online antivirus scanner and a online anti-adware/malware/spyware scanner in safe mode with network to clean up your computer BEFORE you download anything.

Turn of system restore before you boot up in safe mode with network.

To get in safe mode tap F8 when booting you computer.
Choose "Safe mode with network".
Go to Start – Run - type iexplore http://www.bitdefender.com/scan8/ie.html Enter(ok).
Do a full system scan. If something is found, delete it, reboot and do the same again in safe mode with network.
When that scan does not find anything you reboot again in safe mode with network.
Go to Start – Run – type iexplore http://www.ewido.net/en/ Enter(ok).
Do a full scan. If you find something, delete it, reboot and do the same again in safe mode with network.

**NOTE: Do NOT do anything else with your computer when scanning. This because you can start virus/adware/spyware/malware manually.

When no one of these scanners are showing anything you can reboot back to normal mode.
Turn on system restore.
------------------
You need to get one antivirus program, one firewall and some spyware/adware/malware removers if you don't have it.
I use Norton Internet Security on my desktop running XP Home SP2 with Firefox.
On my laptop i have Ubuntu 7.04. No security needed in Linux, but i have antivirus and firewall.

Here are some free programs.
BitDefender Anti-Virus Free.
http://www.bitdefender.com/PRODUCT-14-en--BitDefender-8-Free-Edition.html
Avast Anti-Virus Free.
http://www.avast.com/eng/avast_4_home.html
AVG Anti-Virus Free.
http://free.grisoft.com/doc/2/lng/us/tpl/v5
Avast Virus Cleaner - free virus removal tool.
http://www.avast.com/eng/avast-virus-cleaner.html

Firewall Protection.
ZoneAlarm Firewall Free.
http://www.zonealarm.com/store/content/catalog/products/sku_list_za.jsp?dc=34std&ctry=&lang=nb&lid=trial_zaFamily
Easy-to-use firewall blocks hackers and other unknown threats.
* Systematically identifies hackers and blocks access attempts.
Automatically makes your computer invisible to anyone on the Internet.
Use ZoneAlarm if you normally use Windows Firewall.
Disable Windows Firewall after downloading ZoneAlarm if it's not done automatically.

Ad-Aware 2007 Free.
http://www.lavasoftusa.com/products/ad_aware_free.php
Ad-Aware 2007 Free remains the most popular anti-spyware product for computer users around the world, with nearly one million downloads every week. Our free anti-spyware version provides you with advanced protection against spyware that secretly attaches and takes control of your computer, resulting in aggressive advertising pop-ups, sluggish computer activity, even identity theft through stolen bank details, passwords, and credit card account numbers. If you want real-time scanning capabilities, consider upgrading to Ad-Aware 2007 Plus for real-time protection against spyware, all the time.

SUPERAntiSpyware Free.
http://www.superantispyware.com/

AVG Anti-spyware Free.
http://free.grisoft.com/doc/20/lng/us/tpl/v5

Spybot-S&D Free.
http://www.safer-networking.org/en/mirrors/index.html
Spybot - Search & Destroy detects and removes spyware, a relatively new kind of threat not yet covered by common anti-virus applications. spyware silently tracks your surfing behaviour to create a marketing profile for you that is transmitted without your knowledge to the compilers and sold to advertising companies. If you see new toolbars in your Internet Explorer that you haven't intentionally installed, if your browser crashes inexplicably, or if your home page has been "hijacked" (or changed without your knowledge), your computer is most probably infected with spyware. Even if you don't see the symptoms, your computer may be infected, because more and more spyware is emerging. Spybot-S&D is free, so there's no harm giving it a try to see if something has invaded your computer.

AVG Anti-Rootkit Free.
http://free.grisoft.com/doc/39798/lng/us/tpl/v5
AVG Anti-Rootkit is a powerful tool with state-of-the-art technology for detection and removal of rootkits. rootkits are used to hide the presence of a malicious object like Trojans or keyloggers on your computer. If a threat uses rootkit technology to hide itself it is very hard to find the malware on your PC. AVG Anti-Rootkit gives you the power to find and delete the rootkit and to uncover the threat the rootkit is hiding.

CCleaner free.
CCleaner is a freeware system optimization and privacy tool. It removes unused files from your system - allowing Windows to run faster and freeing up valuable hard disk space. It also cleans traces of your online activities such as your Internet history. But the best part is that it's fast and contains NO spyware or adware.
http://www.ccleaner.com/

ClearAllHistory - clears browser history, cache, cookies, clipboard and remove other computer activity tracks.
http://www.clearallhistory.com/delete-passwords.html

*NOTE: Only have one antivirus program and one firewall installed on your computer.
Anti-adware/malware/spyware are ok to have more of.

Also scan with online scanners sometimes.
http://security.symantec.com/sscv6/home.asp?langid=ie&venid=sym&plfid=00&pkj=VOONYHGBYNCJEIMXQKC&bhcp=1
http://www.bitdefender.com/scan8/ie.html
http://www.ewido.net/en/onlinescan/
http://www.kaspersky.com/virusscanner
http://support.f-secure.com/enu/home/ols.shtml

Hope this was helpful.
Good luck.
JTB - Security adviser from Norway.

Answer 2

If you've heard the story about 'trojan horse', then it's something that comes attached and disguised in something else.
So you need to get a infected executable in your computer to get trojan horse. You could've downloaded it or received via any other means.

Answer 3

I don't know what you mean specifically with "trojan horse" but you can get spyware and malicious programs by just having your computer connected to the internet without a firewall or anti-spyware.

Answer 4

No, there is also what is known as "Drive By Downloads", your pc is infected just from opening a webpage with embedded hidden trojan virus or viruses.

If you have good antivirus software that protects you from "drive by downloads of trojans", then you are secure, if your antivirus is not all that great then you have a problem.

My antivirus I pay a one time fee for life of $29.00 and I get all updates automatic, and all new versions for life. Plus I am protected from these types of drive by trojan downloads.

http://www.filseclab.com

Minddoctor, France