The WiFi on my Latitude D510 started acting up a few days ago, and now it doesn't work at all.

At first, it would disconnect from my home wireless network and then say it could not connect to it. Then it told me that a network adapter (wireless card) was not installed. After I got it to recognize the wireless card again, it told me the driver was not installed. After I got it to recognize the driver, things worked fine for a little while, then the cycle began again -- could not connect, then no adapter found, then no driver installed. I swapped out the wireless card from an old D510 that had a fried motherboard, and it still said no adapter was installed. Restarting the laptop multiple times or using system restore sometimes help briefly, but then it goes right back to telling me no network adapter is installed.

So, is there any way to know whether the problem is something other than the wireless card going bad? I'm trying to decide whether to buy another wireless card and hope it works or to get a USB WiFi adapter instead. I don't want to get a new wireless card and have it not work because the problem is actually elsewhere.

Any ideas or recommendations?