I need professional help regarding a suspicious file?

[Nuhash9]

Can a professional programmer please tell me what this file does to the computer when executed?
http://208.131.138.218/imagedl.php

I mistakenly opened it after downloading it off a spam on facebook. It was a stupid mistake.
I have an antivirus program, but surprisingly, it didn't pick it up as a malicious program or any of that sort. I just figured my friend found a wall post on his wall by me which I didn't post. It carried a random sentence and a short url to the same type of file. I guess that's what it does. How do I get rid of it? Thanks for your answer though!

[Pulsar]

OK,
Here is what it is.

Win32/Agent.OBA Analysis

Win32/Agent.OBA is detected as a nasty Trojan that may severely compromise security integrity and saved files, sensitive information and users’ credentials. All collected data will be saved as a log and send to sponsored distant server whose location or address are mostly injected into the Trojan code which implies that it fetches other components from a fixed place. However, there are also occasions that such tasks are sent out from from a remote attacker.
Win32/Agent.OBA is a new member to the Win32/Agent family. There are also various reasons why authors are releasing Win32/Agent.OBA to target multiple Windows computers. This initial threat is literally small in size and aggressive enough to sneaks into the computer while bypassing detection. When running in the system, it greatly affects the overall system performance and the most significant effect is on web browser performance which will result to browser crashes. That is because Win32/Agent.OBA consumes resources more than what the PC can handle. Other changes, including commercial ads on common sites where there is none prior to the infection, and random failure to upload or download, are also caused by modification on web browsers. Besides, it’s believed that this Trojan is closely in league with Google redirect virus which tries to mess up the affected browser causing numerous redirects to its promoting websites.
Besides, the Trojan is also observed to drop more threats and execute them on the same machine. In addition, there are variants created to allow unauthorized access to the ailing system to reek further malicious activities. As told, Win32/Agent.OBA is a multifacet threat, thus timely and effectual steps must be taken to completely remove Win32/Agent.OBA once upon the detection.


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