How Do i Update The BIOS Of Sony VAIO TX790P Laptop?

Are you able to use any other USB devices without having Windows crash?  There's a good chance that your battery is just dead.  Laptop batteries are known for a short life span.

The BIOS doesn't go bad by itself. Unless you've done some major O/S changes, this is highly unlikely to be a BIOS problem. The battery, as suggested, is a much more probable culprit.

The USB wireless card problem is probably a drivers problem (for the card itself or for USB generally) or a power issue with the USB port. Re-installing drivers for the card and for USB could help.
/RID

Update: I received the new battery and it charges fine so far. I get the same error with the Verizon Broadband card (both the old and the new one they sent me). On installation the card has a step to make sure the latest drivers are being used. I will check out other USB devices and see if those drivers need updating. Thanks guys. I'll check back in later.

When you say the system closes, do you mean the computer either blue screens and then freezes or does it restart?  You can check in C:\Windows\Minidump for the .dmp files.  Run them through the Windows Debugger to see what is really causing it to do that.

Do you have a USB mouse or keyboard that you can connect to this laptop to test and verify that the USB ports are okay?

Update:

This is an ongoing saga. I tried other things in the USB port and they work. Is this actually called a USB port where the wireless card goes? Because it's a card slot. Are the USB ports and the card slots linked? Also I made a mistake in the age of my computer. I actually bought it last year so it's only one year old. As I mentioned it's already been to Sony once, and they stripped it clean of all the settings and configurations it had. Whatever they did rendered the battery unchargeable and it was less than a year old.  I've never had to replace the battery on any laptop I've ever owned and I've owned many. I didn't tell them about it. I just bought a new one. The Verizon cards both old and new work fine on 2 other laptops I have which are running Vista. The problem computer is running XP which I am told should not be a problem.

The blue screen I get is a little blue square which says (copied from another board):

*** Hardware malfunction
Call your hardware vendor for support
NMI: Parity check/ memory parity error
*** The system has halted***

The screen at that point is totally frozen, and the computer must be rebooted manually.

The laptop has been to Circuit City a couple of times for their FireDog people to look at it. The error was reproduced, but no one knew how to fix it. Same thing with a Verizon shop. Since the laptop came back from Sony with all these new problems, I think I'll just have to send it back again and see what they can do.

I'll keep you guys updated. Thanks.

The "card slot" is probably a PCCard (or CardBus) slot, or even this new thingy, PC Express or whatever, but very likely NOT a USB port. Slots ar for housing cards that have like 30 connector holes in 2 rows, USB connectors are usually the same old little rectangle with a metal sleeve and four contact prongs inside.

The problem can be your PCMCIA controller or the slot itself gone bad, or the card(s). You should try the machine on a different O/S (like Knoppix; live CD > no installation) and see if the card slots can be used at all. Try any kind of card (memory, modem, NIC) in the slot and see if it's detected. If yes, proceed with the problem card. What happens?
/RID