evil little script infection

So initially it disabled my audio driver, and i went oh nothing LUL.
Start>Settings>Control Panel>Device Manager>REINSTALL>Opened Sound Manager then left it open. Good luck, doing that again and low behold it stayed installed. Next thing i went to log into my runescape account and ALL my members stuff was missing over 7,8 Mill worth of stuff easy. And then I went to log back in and someone else was logged in - This was after I changed my password.

I went into msconfig disabled all remote services ran a anti virii and a screw of 17 infectious items came up. THEN, Finally something was cloning itself I don't know what and eating up my HDD space continuously until there was literally NO HDD space left on the primary boot partition. I dual boot win7 ( which I kinda hate) and xp pro sp3. So I finally went oh god eff this and booted win7 only problem is drive L: prompt of low space which is not the install partition for this I have Multiple Partitions and two HDDS.

Kinda pissed about getting ripped on runescape but a little more worried about my paypal and credit card staying safe.

Thinking about totally formatting that HDD from win7 then writing zeros to it and saying eff it. I keep all my big important files backed up on an external HDD which is almost filled anyway without a malicious script.

Any Jedi advice? For I am still a Padawan somewhat.