Thanks for the replies guys,
I had another look based on your questions, I think the issue now is whether my usb adapter supports n-network
The two other PC's are able to download at 6.6. MB/s (downloading separately) whereas I am limited to 3.3 MB/s (downloading separately)
I hover over my wireless network status and noticed that the speed connection was 54 Mbps whereas the other wireless PC is 64 Mbps.
It states that my radio type is 802.11g; the other wireless network has radio type 802.11n
My USB adapter is USR5421 Wireless MAXg USB Adapter
If it does support the N network, how can I switch the settings in Windows 7?
The other PC which receives the max speed has the following adapter
TP-Link 150Mbps High Gain Wireless-N USB Adapter
edit: meant MB/s not Mb/s with regards to download speed