Please go here and have these files scanned. Post the results back here.

C:\WINDOWS\lajisvc.exe
C:\WINDOWS\lajienc.EXE
C:\WINDOWS\switpa.exe
C:\WINDOWS\lajidll.exe
C:\Program Files\winupdate\winupdate.exe

Clear out your Temporary internet files and other temp files.
Go to Start > Settings > Control Panel >Internet Options.
Under the General tab click the Delete temporary internet files,
delete all Offline content as well. Clear out Cookies.

Also, go to Start > Find/search > Files or folders > in the named box, type: *.tmp and choose Edit > select all -> File > delete.

Empty/delete the entire contents of the C:\Windows\temp folder and C:\temp folder, if you have one. (Contents but not the folder itself.)

C:\Documents and Settings\username\Local Settings\Temp\

In order to view these files you may have to select 'show hidden files/folders.' Instructions on how to here.

Empty the Recycle Bin.

Post back a new hijackthis log with the results of the online scan for each of the above files.