Computer infected with malware? help!!!?

[292]

Today I was browsing the web on google chrome and my computer started downloading some .exe file without my permission. I immediately cancelled the download so it wouldn't be completed. The file didn't get downloaded completely, so I guess I should be safe? I also didn't open anything, I cancelled it while it was downloading and deleted the unfinished file from my downloads-folder in google chrome.

I should be safe, right?
Even if it had downloaded completely, I had to execute it first before it would actually cause any harm, right?
Anyway, according to the download-folder in chrome it wasn't downloaded completely so there's no need to worry then.

[The Necron]

if it was on a page that had a download on it your good but if not you might be infected with a trojan

[RaNdOm]

When you go on a page, a site can automatically give a download. And Chrome is a browser that automatically accepts anything. And if the file was not downloaded all the way, that means all the script was not all there, which means it would be corrupt if it tried to run on your computer, it wouldn't work. And it wouldn't be able to do that anyways, without Administrator properties... You're definitely safe. Don't worry one bit, take it from a professional.

[Nahum]

The download may have been cancelled, but what caused it in the first place?

Perhaps you just visited a bad site. Worse, you might have some hidden malware or browser plugin that initiated the download, and is waiting for another opportunity when you aren't paying as much attention.

Definitely give your computer a thorough scan in Safe Mode with antivirus and antimalware software. Microsoft's own Security Essentials is a pretty good antivirus program for being free. Malwarebytes has a good antimalware scanner, while Spybot Search & Destroy has an "Immunization" feature that can prevent your browsers from wandering into trouble.

You can also use programs such as Autoruns or HijackThis to see what programs are set to self-start, research suspicious entries, and remove those that don't belong.