Question : Problem: sound and audio device problem under windows

Hello every one, I have a problem with the sound and audio device of my desktop computer. This is my sister's computer. OS is Windows XP Home Edition. Chipset on main board is Intel 845GL. Sound card is ALC201A which is integrated on main board. Computer can't login in few days ago because of virus. Now I think I have deleted all virus and I can login to windows. Everything seems working as before except when I run a media player which can't work and reports an error: There may not be a sound device installed on your computer, it may be in use by another program, I checked in device manager and AC97 audio is working fine with no conflict. However when I checked in sound and audio device property in control panel it shows no audio device. I have checked that audio in COMS is AUTO. Windows audio service is running. And I have Plug and Play Software Enumerator working with no error. I have reinstalled the driver several times and still cant work. Does anyone can help me?  And sorry for my poor english.

Answer : Problem: sound and audio device problem under windows

That leaves the OS or the motherboard sound controller as the probable cause.
I wold be more inclined to suspect the OS due to our previous trouble with virus's. At this point you may need to do a repair install of XP but I don't know if Lenovo's XP version supports that option.
Perhaps a system restore to before the virus issues. Or lastly, backup all important data and a clean install.
Can you definitely put the loss of audio at the time of virus removal?