Can't connet Netgear AP HELP

I have a IBM laptop R40, it was used to connect to a D-Link wireless network without any problem. So I know the laptop side is OK.

Now, I have to use this netgear MR814v2, I disable the wep, and enable the access point and broadcast SSIN, and try different channels...my laptop can find the SSIN with 80-100 percent of signal and right channel number, but when I try to connect, it always always told me can't connect!

I don't know what is the problem, I can even connect to some nearby access points with signal like 20%, but not my own with 80%...Is there anything else I should try?

The firmware is V5.3 on router and I just upgrade all drivers on the laptop.

Thank you in advance for any suggestion!!!