PC and mobile phone won't connect.

Hi
I don't know if this should be under windows or hardware.
Mobile phone--samsung J700. Windows xp pro.
When i bought the phone i installed the software and esablished a connection through USB and everything worked fine.
I had to reinstall windows after formatting the hard drive,and everything worked except
when I reinstalled the samsung software I was unable to get a connection.
I get a beep when phone is plugged in and again when I unplug it.
Message on phone mentions "mass storage device".Phone starts to charge when connected to USB.
Device manager has yellow ? against "other devices"
I've uninstalled and reinstalled samsung software and USB driver.
I've d/l latest software from samsung site and installed that but still no connection.I've tried software on another PC running xp home but still no connection.
Anyone got any ideas?
Is it the phone, the USB cable, a fault with the drivers or is windows stopping the connection for reasons known only to Microsoft?
As I said before it workeduntil I had to reinstall windows but why wont it work on two separate PCs.
Help please!!!

have you installed all of your motherboard drivers etc?

Are you connecting it to the same USB port as before, maybe it needs a USB2 port and not a USB1. (speed difference)

just a few ideas till someone else gives you expert help lol

Thanks
Don't know about the motherboard, other USB devices are working.
I've tried plugging into USB1 and 2 ,doesnt work on either. The peculiar thing is that I can't get a connection on the spare PC, this PC had not been tampered with!!!!!

Problem solved!
A setting on the phone had changed, don't know how cos I didn't even knoqw it was there.
There was still a problem as windows recognised there was new hardware but couldn't find the driver even though it was on the installation disc.
I did a system restore to a date before windows updates were installed and I reinstalled the driver---- connected straightaway. So I don't know what caused the fault but its fixed.
Thanks