Studio 15 wireless connection problem

hi, i hv bought a studio1535 with 1397 wireless card from bestbuy recently. everything work fine during the first 2 wks. and then, all of the sudden, i was unable to connect to ANY wireless network. the wireless card is able to search for usable network, and some of them are in great strength. but everytime i click on connect, it go direct to the diagnoses/connect to other network window. my laptop can only connect unless i stand RIGHT NEXT TO the router, once i step away for like 3,4 feet, i wasn't able to connect anymore. could anyone think of a solution for me please!!! *note* i am able to connect with the lan cable plugged.

i guest it should be some software problem since the adapter is able to find avilable network. and also, i have run the hardware diagnosis for the 1397 adapter, and it passed everything.

here are a list of wt i have tried to fix:
1. undate driver - doesn't work
2. uninstall driver and then install the most update one again - doesn't work
3. update bios - doesn't work
4. restore to a earlier restore point - doesn't work
5. format the machine and reinstall vista - doesn't work
6. close down all firewall - doesn't work
7. turn on network searching in the network and sharing center - doesn't work
8. disable all the security setting in my router - doesn't work

since 14 days has been past, i cannot return it back to BestBuy. also i have check my warranty status in dell.com, it saids its expire (i have no idea why).
i think i probably have to fix it by myself.

please, could anybody come out a solution for this!!! thank you very much

 

try openning the panel and checking that the antennas are connected properly. maybe one came off.

 

u think that's a hardware problem? ok thx, i will give it a try