HELP please

My computer got infected with a win32: vitro. im not very good with computer stuff and i would just like to ask some help please. the file infected was :\windows\system32\drivers\nvlddmkm.sys and C:\Windows\System32\DriverStore\FileRepository\nv_disp.inf_67802caf\nvlddmkm.sys
how can i remove the virus or fix the file?

Will this help?
http://forum.avast.com/index.php?topic=42916.msg358778#msg358778
http://forum.avast.com/index.php?topic=42926.msg358864#msg358864

Do a manual VPS update and rescan the files.