USB Problem. Driving me nuts!

It may be coincidental, but I bought a memory stick off ebay which turned out to be fake. Since that time, I found that every time I turn on my Acer Aspire laptop it will not recognize anything (stick, drive, camera, ipod etc.) plugged into the USB ports or a card in the memory card socket.
No messages or anything, just no reaction to anything plugged in.
DeviceManager shows nearly all the ports (Intel ICH9 Family USB Standard and Enhanced Controllers) and the USB Root Hub(s) with little yellow exclamation marks.
At first I uninstalled all the hubs manually and restarted the computer and this got the hubs working, but next time I booted up, the same thing had happened and I had to go through the whole thing again.
I then found that the Troubleshooter and Windows Fix It (ha ha) would reinstall all the hubs automatically, but they would still be corrupted next time I booted up, so I had to go through the whole rigmarole again to use the USB ports.
Each time i use the Troubleshooter it fixes all the ports, but I get a message - "Hardware changes might not have been recognised" and a yellow warning triangle.
Fix It does exactly the same with nothing else to offer regarding the "Hardware changes...." message.
Next time I start the computer I am back to square one!
I have tried updating the drivers - I always get told they are up to date.
My computer OS is totally up to date with "Windows Update".
I always remove the USB devices properly.
Another post elsewhere suggested checking that the Windows Installer in Services is set to Automatic - it is.
How do I get it to recognize the hardware changes so that it starts up with all the ports working every time?

What is your computer model ?

Its an Acer Aspire 5732Z. Intel T4300 processor.

This has been going on for about a month now and I have looked at lots of similar posted problems for help. This "hardware changes..." message seems to be generated a lot when people have problems with sound, and there are other problems with USB ports on Win 7, but I have not seen a post about my particular problem anywhere, except for one poor soul with the same thing who posted a cry for help on another forum but got no replies.

I've tried updating the drivers. They are up to date. even tried updating via the net. same result.
One thing that puzzles me is that it has 7 USB controllers and 7 hubs in Device Mangr, but only two physical ports and one card slot on the laptop. I'll try the chipset update and report back Thanks.

Thanks for that USB info.
The stick was all packaged right and looked like a real Kingston stick, but instead of being the size advertised it was just 4gb.
I seem to have had problems since then.
I went to the Acer site and found the Chipset Drivers it recommends (2009), but when I tried to load them I got a "these are older than the installed ones" type message. 9.1.1.1015 instead of 9.1.1.1020. So I didn't install them.
I went to the Intel site and the Chipset they show as 9.1.1.1020 is for XP and 2003 so that seems to be just a revision number. .
There were loads of other free chipset download sites on Google, but they looked very dodgy!
Intel do a chip ID check, but it does not support Win7 64bit, so I am not 100% sure which chipset I have. Intel update checker says its a 6, 5, 4, 3, 900 type chipset.
As I have not updated chipset drivers before, should I just the earlier version, or should I load one of these latest .inf chipset files?Support for the Intel® 945 Express Chipset Family

I think this should do it:
http://downloadcenter.intel.com/Deta...odId=undefined

Thank you for your help so far but:
I installed the chipset drivers and it has not made any difference. When I start the laptop all the USB ports and hub are u/s. I have to run the troubleshooter and this restores them to normal, but with the same "Hardware changes..." message. They work until the PC is turned off but when I turn it on again I have to use the troubleshooter again to get them working.

Check this out: Hardware devices are not working or are not detected in Windows