Dell 9200 Laptop USB Ports not working

Have you checked in the device manager to see if there are any indicators showing problems.
to do this click-->START-->RUN type in "devmgmt.msc" and click -->OK
In here click the [+] sign to open the--> Universal Serial Bus Controllers   check if there are any yellow or red marks next to the Universal Serial Bus ports.
post back here with your info.

I was a dell field tech for a while. If a reinstall did not correct the issue and you do not have a warranty, your best bet is to get a 9200 with a broke screen from ebay and do a motherboard swap. These motherboards had a problem with a component that caused the usb system to just quit responding. I can give step by step instructions on the replacing, all you need is a small phillips screwdriver. Sorry for the bad news.

Did you reinstall service pack 2 as well?
It has USB fixes..

First check inside the BIOS, there may be a "Legacy USB" setting or something similar. If that doesn't help, get Knoppix, boot with that CD and try the USB things with that. If it won't work there, you have a hardware problem and your best option would be to buy a PCCard USB (and if possible combined with firewire) adapter.

Forgot the link to knoppix, sorry:

http://knoppix.net

rindi,

what do you mean by "try the USB thing"...once I download Knoppix, what do I do.  ??

You burn the iso to a CD using nero or a similar CD burning software that can burn iso images, then boot your PC with that CD and check if a USB mouse works. Knoppix is a linux distro that runs completly off a cd and doesn't write anything to HD. It starts a GUI similar to Windows and has very good plug'n'play support.