Alright USATECH and SMELLS, I am the sort of person who thinks along the lines of "If it aint broke don't fix it"
I try to stay away from microsoft updates and service packs until I know there is something in them that I need, mainly because in the past I have found that they can cause more problems than they solve.
My thoughts on you problem are that it either has to do with your diligent updating or there is an IRQ conflict, I have no idea if you know what an IRQ conflict is so I will give a simple explanation.
Your PC has a set amount of IRQ's this stand for Interuppt Request, they are used by your PC basically to judge the priority of the device. However that doesn't mean you should go changing things around to suit what you think should be given more priority. Most of the IRQ's are actually already reserved and used by things like your mouse, keyboard, motherboard functions etc. If the PC has an IRQ conflict then the conflicting devices may or may not work, or might only work sometimes.
To solve an IRQ conflict use your device manager to see if the devices are conflicting and what they are conflicting with, then look to see if you have any free IRQ's, if you are using Win 2000 you can do this by selecting the view resources by type in the device manager.
Some commonly free IRQ's are 5, 7, & 10. Also if you are not using the COM ports you can disable them in the Device manager and use their IRQ's, remember don't remove them just disable, if you remove them they will be detected as new hardware when you boot up next.