Try running
Trendmicro's anti-spyware program, as it includes a scan for some forms of browser hijackers in addition to the normal run of spyware out there. I'm not certain how effective it is specifically against keyloggers, but since those are classified as hijackers, this should stand a chance at getting rid of it.
This page also has several tools that can help, specifically startuplist and hijackthis. Read the descriptions on each to see which sound applicable. Lastly, like Echo recommended, update and run all these tools in safe mode to have the best odds at removing anything that has infected your computer.
Jam it back in, in the dark.