Latitude D620 with Dell Wireless 1390 Minicard and Belkin Wireless G Router

Hi,

I am having a Dell Latitude D620 laptop that has a Dell Wireless 1390 minicard.
I am using a Belkin Wireless G router connected to a PPPoE broadband internet connection. I have setup the wireless network using this router. I am able to connect to this wireless network using the dell wireless connection utility. The laptop also gets an IP address and the WAN network works fine. But, there seems to be a problem with the internet access. The internet works intermittently. Sometimes while browsing, the pages load without a problem. But, soon they stop loading for a while. This cycle continues to occur throughout, eventhough the wi fi signal strength is continuously healthy. I tried my friends toshiba laptop and there is absolutely no problems for the same setup of the router. What could be the problem? Are any of my settings incorrect? Please help me out.

My router important settings are as follows:

Wireless:
Wireles Mode= Mixed 11b+11g
Wireless Channel= 11
Security:
Client Type= WPA/WPA2
Authentication= PSK
Internet:
Connection Type= PPPoE
MTU= 1400
DNS= Automatic from ISP

My Laptop Card (1390 minicard) settings are as follows:

Driver: Broadcom 10/12/2006 v4.100.15.5

802.11h+d= Loose 11h+d
Afterburner= Enabled
Antena Diversity= Auto
AP Compatibilty Mode= Higher Performance
Bluetooth Colabration= Disabled
BSS Mode= Default
Disable upon Wired Connect= Disabled
Fragmentation Threshold= 2346
IBSS 54g protection mode= Auto
IBSS Allowed= Enabled
IBSS Mode= 802.11b/g Auto
Logically Administered MAC address= Not present
Manage Wireless Settings= Enabled
Minimum Power Consumption= Disabled
PLCP Header= Auto (Long/Short)
Power Save Mode= Disabled
Radio= Enabled
Rate= Use best rate
Roam tendency= moderate
Roaming Decesion= Default
RTS Threshold= 2347
SSID Autopromote= Disabled
WLAN Priority support= Disabled
WMM= Auto
WZC IBSS Channel Number= 11
WZC Managed Ethernet= Disabled
Xpress Technology= Disabled

Hope this information helps.

Regards
Aditya