No access to shared folders

Similar Problem But....

Hi ! Since weeks , I am struggling with the following problem : My two PC's are on a network (the laptop is connected to the gateway -router by a PCMCIA card )All physical connections are Belkin; there is no conflict; however while both pc's see each other perfectly and the network seems perfectly parametrized , several drives on which I activate all possible SHARING PROPERTIES , produce the same strange error messge when I try to open them : you do not have access to this folder or this folder is inaccessible aso ...
On the other hand some of the drives on which this happen are external drives connected to the desktop PC by USB2 and when I try to "safely remove hardware" meaning I would like to remove them from the PC just to check , it reveals impossible : the messge is:" cannot stop this right now" ; are the two phenomena connected ?; it never happened to me before ; usually all drives could be accessed without any problem ; I just changed the Hard Drive on my laptop and had to reconfigure the network to my greatest disppointment ; the problem does not prevent me to work , but I would be very happy to get rid of it ; Belkin support does not give you this type of advice any more as they used to do one year ago ; they just focus on hardware problems ; the rest is Windows ; that's what they say. Thanks for any help that could solve this ; the afore mentioned Trick is clearly not pertinent here .OLIVIER GEBUHRER