I dont know how to install the software for my camera eee pc series notebook

there must be a disk that came with laptop for reinstallation try using that and finding the software for your camera and if not go to the acer site and search for the drivers according to your model number then you can download the particular driver and software for the webcam and it should start working again. And if not then try re-installing windows as many times OS gets corrupt.

To turn the camera on IS in the BIOS. It's not in a logical "camera" spot but it's in there. My camera on my Eee PC 1000H got turned off somehow (not by me or by a BIO upgrade) so I found it and fixed it. Look for it in the BIOS menu's. It's there.

There are 2 ways to install xp on eeepc.

1) Use usb flash drive 2gb minimum

2) Use usb CD-ROM if you have one.

run your system/recovery disk and look for your webcam software and try to reinstall it

go to this link might help you.
sounds like drivers are missing or software missing.Systems software includes the operating system and all the utilities that enable the computer to function. Applications software includes programs that do real work for users. For example, word processors, spreadsheets, and database management systems fall under the category of applications software.

What is Software? Webopedia Definition..

or this link. web camera is not found Google Search

Run system restore. this is a malfunction.

Use the below software to capture images from webcam

http://amcap.en.softonic.com/

You should be able to use the AC97 HD codecs available from Realtek with your sound device.

Post your results under this thread, especially if you continue to have problems after installing the driver.

First: Go to Run>Settings>control panel> Scanners and Cameras> Do you see camera?
If not, do next:
Go to BIOS and Enable it.

here you can download the audio driver(For Win XP):
http://www.2shared.com/file/2978932/261e8259/Audio.html