Windows 7: USB mass-storage slow to be ready for access

Hi!

I've been through a very singular problem for the last few days.
My Windows 7 suddenly become slow to make USB Mass storage devices ready to access, but this happens only the first time I connect them on my computer.
If I start the computer and connect the USB Mass storage device (that was recognized a long time ago) it takes almost 1 minute to be ready for use... After that, every USB Mass storage device that I connect to the computer opens almost instantly.
If I restart the computer, the same thing happens.
I've tried to reinstall drivers, to disable security, looked for a service that controls it, verified the power options and verified every hardware...

Where is the problem? Can somebody help me?

Have you checked in Device Manager for any conflicts, particularly on the USB controllers?

You haven't posted your specs, so what is your computer's power supply rated at?

Have a look in System Information by typing msinfo32.exe in the Start field then press Enter.

Navigate to Hardware Resources>IRQs and check what's in the right pane.

It would be helpful if you can give us a screenshot of the information.

Yes, I looked for any hardware conflict and I didn't found anything.
I tried to remove and instal all drivers related to USB but this didn't solve the problem.

I posted my specs on my profile now, you can see it there.

The screenshots of msinfo32.exe>Hardware Resources>IRQs are here:

I tried to find the problem all night long, but I couldn't see what is wrong!

The BIOS is ok.
The drivers are ok.
The hardware is ok.
The system services are ok...
I tried to do a System repair and nothing changed...
I tried the solution I found here on sevenforuns to repair Seven when the devices are not recognized anymore and it didn't worked too.

I don't know what to do anymore...
Can anyone here help me?

As stated earlier, post a screen shot of your device manager, another possibility your at the miniumn of 2gb of ram. Just some possibilities

There is no problem on my Device Manager as you can see:



So, do you think I need to upgrade my computer?