Wireless is usually about half the speed of wired even with good wireless reception. You should try to optimise your reception and avoid interference.
1) raise the router above furniture level
2) Experiment with channels (some will work better or worse depending on your environment)
3) If you can detect strong neighbouring wifi, use a channel 5 stops away from strongest.
4) Relocate cordless phone base or video sender etc.
5) Be prepared to move the computer (or at least turn it so your body is not between the router signal and the wireless adapter's antenna.
Thanks Fihart, but all these would be the reasons when I was also not getting enough wireless speed for the internet access too. The internet on wifi from the same computers work like a breeze! And internet is also on the same channel of wifi. It is just the PC to PC speed that is slow. Surely it is a configuration issue and not a wireless interference or wireless transmission issue.
I guess this problem is a universal problem but the responses are so varied I don't know which ones to start working on. I surely don't believe it is a wireless interference issue unless the computer to computer channel is separate from the computer to internet channel. And by the way we have nothing near the desktop that emits radiations (except perhaps a TV). Anybody else wants to give any insights?