How to update unity web player

I have installed Unity web player 4.0.1f2.I want to play "Motorcross Nitro" on miniclip.com.But whenever i try to play it it says on loading screen: "Failed to update unity web player, Errors Details, Install Manually" when after installing unity web player i run the game the downloader just pops up and give me file to download named "UnityPlayer3.x.x-win32".i extracted the file and put it into "C:\Documents and Settings\yaqoob\Local Settings\Application Data\Unity\WebPlayer\player,but it's no use. when i click on error deatails it tells me that a new version of unity player is availaable but autoupdate failed.I tried to manually update it from "C:\Documents and Settings\yaqoob\Local Settings\Application Data\Unity\WebPlayer".but it does not work. when i click on install manually it takes me to http://unity3d.com/webplayer/. i installed it manually from there but still did not work. I cleared the cache of chrome and Firefox a lot of times. My PC specs are: Pentium4 CPU 3.2 GHz 1 GB memory Express chippest family VGA 128 mb Windows XP service pack 2 Directx 9.0