Doesn't sound like it's got anything to do with hackers - sounds like you've been visited by the Sircam e-mail worm. Or W32.Sircam.Worm@mm to give it its full name - it arrives as an attachment to an email message.
Information available here...
http://[email protected]
You must still have an entry in your startup files that is attempting to launch the worm SIR32.EXE
I suggest you get the full removal tool and instructions from Symantec.
http://www.symantec.com/avcenter/ven...oval.tool.html
But it seems likely that the key step that is needed is this...
To edit the Autoexec.bat file:
1. Click Start, and click Run.
2. Type the following, and then click OK.
edit c
autoexec.bat
The MS-DOS Editor opens.
3. Remove the line "@win \recycled\sirc32.exe" if it is present.
CAUTION: If you see more then one entry of "@win \recycled\sirc32.exe" in the Autoexec.bat file, it means that the computer was infected more the once. Because of this, the Run32.exe file will have been overwritten with an infected copy of the Rundll32.exe. As a result, you will not be able to rename the file to recover it as directed in the next section.
4. Click File and then click Save.
5. Exit the MS-DOS Editor