on xp to set up a adhoc
1) , right click wireless adapter and then click properties.
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2) Wireless Network Connection Properties will appear. Click Wireless Networks tab, here I tick Use Windows to configure my wireless network settings. After that click Advanced button.
Wireless Network Properties
3) Advanced window will appear. Select Computer-to-computer (ad hoc) networks only option. Click Close at last.
Ad Hoc Mode
4) After that, click Add to add new ad hoc wireless network.
Add Ad Hoc Network
5) Name your ad hoc network, hTry to use open authentication without encryption first. After tested it works well, only proceed to enable WPA or WEP encryption. Click OK at last.
Add Ad Setting
6) Now you will see your created ad hoc network (PC card icon) in preferred networks list. Wooo.. Yoive done