Wi-Fi USB adapter freezes the system?

Hello, THG people...

Two years ago, a lightning strike fried my ADSL router and LAN port on the motherboard (ASUS A7V8X-X) of my now very old system. After that, I bought a Wi-Fi USB adapter (AirLive WL1600-USB) and disabled the fried LAN port.

Since that moment, my computer kept freezing totally randomly for the past two years - it didn't matter whether I run a dozen of programs or simply leave the system alone. I tried reinstalling Windows, but it freezed even with a fresh install, with no drivers or any software at all.

First I didn't know what's causing those freezes, until a week ago. You see, we were forced to cancel our ADSL account for four months, so I haven't used that Wi-Fi adapter for the entire summer (I disconnected it and uninstalled its drivers). During that time - not a single freeze for four months.

A couple of weeks ago, we activated our ADSL account again, so I plugged the Wi-Fi adapter in and installed its drivers - and the freezes started again.

So, should I try with a different Wi-Fi adapter, or simply try with a standard wired PCI LAN card? Updating the adapter's drivers won't help, as I already have the latest version. Perhaps the USB ports are also bit damaged in some way?