Windows computers won't connect to the Internet (LAN or WiFi) but Apple products can.

Around a week ago, all my Windows computers suddenly couldn't connect to the Internet. Here are the details:

• Desktop - connected to LAN. Error: LAN connection / Ethernet Adaptor may have a problem
• Laptop - connected via WiFi Error: "Limited Access"
• Laptop - connected via WiFi Error: "Limited Access"

The service team from my Internet Service Provider tried to connect their laptop to our LAN and WiFi, and both worked fine for them - so they assume that our problem is caused by a virus. The weird thing is, my Macbook, iPhone, iPad, and Nexus 7 can all connect to the Internet with no problems.

Also, it might be worth noting that I can boot into Windows 7 on my Macbook, and can connect to the Internet using this.

Any ideas on this? The only thing I remember doing lately that may have contributed to this problem is that I tinkered with our WiFi security settings (changed it from WPA2 to WPA-Personal) and changed the password. I've already changed the properties for all of my computers to set our connection to WPA-Personal.

Here are the things that have I have already tried (and failed):

• Disabling and enabling the LAN connection (desktop) and WiFi (laptop)
• Hard reset the router
• No changes in any proxy settings
• Reset the TCP/IP Winsock
• Scanned for malware using Malware Bytes - found around 20 and successfully put all of them in quarantine. The only malware found that I think could be connected to my problem is "Vundo".

I can't really pinpoint what virus this could be or if "Vundo" is causing all this (if it really is a virus causing it) because it seems weird that it'd attack 3 computers - all of which have Antivirus programs, and 2 of which I don't even use that much. I don't know much about computers, so any help would be welcome.

Thanks!