I just reloaded Windows 7 on my Acer Aspire 7741G, and now it says I have no network controller, or network adapter, how do I get those back on so I can use my WiFi

I have had the exact same problem with my acer aspire. The name of the network adapter in my 7741g was atheros AR5b97 ive found that there were no drivers installed for this device on my computer but through hours of searching i finally found one that works on a website called pc pitstop.

http://www.pcpitstop.com/drivers/download/Atheros~AR5B97~Wireless~Network~Adapter.html

If you select the downlaod for your specific operating system and version, (win 7 x64 for me) they ask for your email and send you the download link. At first i was skeptical thinking it was another sham driveridentifier type application but they did infact send me the correct driver and I now have wifi access! As for the ethernet controller and pci drivers i plan to download them through automatic updates on my laptop, good luck to anyone else who has this problem.

Download the network device drivers from the Acer WEB site. Makesure you select the model of your laptop the drivers you that require thatmatches the Windows version that is installed on your laptop. Use this link toget to the Acer support: -
http://www.acersupport.com/drivers_download.aspx