gah95on6.exe is bad but I'm not exactly sure what it is. Remove the startup entry and delete the file. If you have more specific information on this file please let us know. Ad-Aware seems to detect and remove it.

There will be a startup entry that looks like this:
O4 - HKLM..Run: [gah95on6] C:WINDOWSSystem32gah95on6.exe