i doubt i have some problems with my USB port..its behaving unusually
when i plug in a pendrive into the port while the system is on,
the entire system freezes,and NOTHING can be done.. the keyboard,
mouse everything stops functioning,i have to restart to resolve it..
so inorder 2 use my usb port, i have to plug in the devices before
windows completely loads..i didnt have any such problem earlier..
and i just switched 2 broadband recently.. i use a dsl modem via the
usb port..i cant use the 'SAFELY REMOVE HARDWARE' for this device..
when i do,the earlier 'freezing' ocurs.. so any1 plz help me..tell me
whether its a hardware problem or just a software fault with the port..
if that is the case will a reinstall of OS be enough?i use windows2000

The DSL modem may already be taxing the current limitations on the USB controller.
USB controllers normally serve TWO USB ports. If you have more than two USB ports then you probably have more than one USB controller.

The solution may be to try a different USB port for either your thumb drive of the modem.

Do you have the pendrive plugged into a USB port directly connected to the mboard, as in one built into the mboard edge, or one directly connected to a USB header on the mboard (e.g. one of two and only two front USB ports on the case, or 2 or 4 ports on a plate in a slot that connect directly to a mboard header)?

If you DO have the pendrive plugged into a port directly connected to the mboard, are you sure you installed it properly? e.g. many devices must have their software installed BEFORE they are plugged in, in order for them to be detected properly and work properly.

If you don't, USB hubs that have more than one port connected to only one directly connected USB port do not work with all devices, even if it is a "powered" hub that has it's own additional power supply.
If you have it plugged into an external USB hub that plugs into only one USB port directly connected to the mboard, or into a port in a hub that might be built into the front of the computer that connects to only one USB port directly connected to the mboard, your pendrive may not work properly or be detected properly.
Other things likely to not work in such a hub - printers, multifunction printer/scanner/etc. devices, scanners, some cameras, etc.

Each USB port directly connected to the mboard is rated to supply a max 500ma (1/2 amp) of current. Most USB connected devices don't draw anywhere near that max current, but some draw a lot more than others. A hub that has multiple ports that share only one directly connected to the mboard USB port share that 500ma capacity if it is an "unpowered" hub (all such hubs built into the computer case or a USB hub card, rather than a USB controller card, in a slot are "unpowered"), or if it is an external "powered" hub, it has an external power supply that connects to the hub so that 500ma can be supplied to every port in the hub if required (you may be able to use the hub with or without plugging it in), but even then, some devices will not work properly or will not be detected properly, and you must plug them into a port directly connected to the mboard.