Hi,
Please let us know the model number of the Acer PC. For Acer PCs and laptops there is generally one of the long, thin buttons on the very front; turning it on will flash “Wireless Enabled” on the screen. Sometimes, it’s the function key (generally F3) to turn on the Wi-Fi, refer to the Manual for the correct key.
To enable the Wireless adapter on your Windows 7, please follow the following steps :
1. Click on the internet access on the taskbar, and click on Network and Sharing Center.
2. Click Change adapter settings on the left.
3. Right click on your Wireless Connection and click Enable.
If, however, the network discovery is turned off you may refer to the link : http://windows.microsoft.com/en-in/windows7/enable-or-disable-network-discovery
Hope this information is helpful. Please do let us know if you need further assistance with Windows, we’ll be glad to assist you.
Thanks & Regards,
Harkanwar