Toshiba satellite pro 6100 very slow

my laptop toshiba satellite pro 6100 is very slow. It is having 512mb ram 1.66 p4m processor,30 gb hdd windows xp os. I severel time reinstalled the laptop.As original Cd is missing (but have genuine sticker is on back) I down load drivers from toshiba's sites (us, europe,etc..) each time laptop showing different problems with display driver's installation. first it crashed when detecting nvidia GeForce4 420 Go graphics adapter which is built in. secon time display resolution cannot adjusted beond 800 x 600. Third time it showed one black stripe on right hand side. All problems solved and now new problem is with graphics hardware acceleration! When playback any video in any player it jerks. Can any one suggest a solution for this and give me a thread for down load a problem free display driver. all other drivers works well.

Another issue is very slow USB speed. I know this is a USB 1.1 (12 Mbps) port. But every time I connect an external hard disk which works properly in other machines it cannot even detected after several minutes. There is no problem with flah drives (usb sticks). If anyone know what i can do regarding this matter pl help me.

Thank you