My mother owns the aforementioned laptop running Windows Vista and it has recently been having a problem. She owns a USB modem K3765 and recently the laptop refuses to recognize it. I have tried it on my laptop and it works fine. The USB ports accept other connections (phone, MP3, Kindle) but not the modem. When the modem is plugged in the blue light flashes on it but the windows explorer or the modems program doesn't seem to register it. As I said the modem works in my Dell 1545 laptop and the USB ports on the V5535 work with other devices. Any help would be greatly appreciated.