Streaming wireless vs wired. Vista & XP

I'm on a 3mbps ADSL 2+ line, using a 10/100 wireless adsl router. When I'm using lan cables, I do not have problems streaming anything between my XP desktop and my vista HP laptop. No issues, no lag.

The problem is, when I just use wireless on my laptop (Dell XPS M1330), even if it is beside my router and signal strength is 5/5, I'm having problems doing streaming.

On my desktop (which is connected to the modem router via lan), when trying to access music/videos on the laptop, it is still alright although there might be some lag from time to time, which i can live with.

However, on my laptop, I'm having problems just accessing the shared folders on my desktop. Streaming/transferring files is virtually impossible as windows try for about 1 min and then give up with a Not Accessible message.

Any solutions? I tried disabled Kaspersky Internet Security on both PCs but it didn't work. I can open small files like .txt files on my desktop using the laptop, no problems. But not big video files

I'm on channel 2, which is not crowded at all. I'm using Dell Wireless 1505 Draft 802.11n WLAN mini-card on the laptop, latest drivers. Strangely, I tried doing the same thing on another laptop on XP with an Intel Pro 3945ABG card and there was no problems streaming from either my desktop or my M1330. Basically, streaming anything between both the laptops no problem...just that my vista M1330 will have problems when accessing files from my desktop