Hi,
I have fedora 10 and installed virtualbox 2.1 and in that virtual box in installed Xp,but my USB can't be detected ,any idea.
I've enabled my USB in virtualbox settings but it's still in Grey color
any idea is appreciated,

Any particular reason you installed such an old version of VirtualBox? Are you using an OSE or PUEL version of VirtualBox? Have you tried running the VirtualBox USB configuration test script posted here?

If your using the OSE edition one of the limitations is no USB, get the other version if this is your issue.

i've tried installing virtualbox 3.1 but got some error while installing ,so just tried the older version and it worked ,no other specific reason

It's a PUEL version and i looked the post that you've given me and i run the script and it works except that the usb is mounting only on my virtualbox not in my main box ,is that the way or can i mount it on both machine

That error might provide some useful information. Can you tell us what it was?
It can be problematic to have the same USB device mounted on both systems so "mounting only on my virtualbox not in my main box" (more clearly expressed as "mounting only on my guest not in my host" is OK.

When you wrote "I've enabled my USB in virtualbox settings but it's still in Grey color" where was it grey -- on the host (including in the host's window for the guest, in the Devices->"USB devices" menu) or in the guest (including in Device Manager)?

Hey
look at this
you can run your virtualization with root privelegs were only have permission to read the usbfs, so if you are runnning your VB from user account it will not detect the usb's.
example:
run virtualization from root account like
# Virtualbox

Sorry, i've installed 2 guest OS in my virtualbox ,so i don't want to redo it again,so i'm okey with this version ,nothing seems to be wrong at this point of time

In this point i have a doubt ,i can can connect my CDROM in both OS ,but why treating USB in different way .
Next time it will be proper

If it ain't broke don't fix it! Actually you should not have to reinstall the VMs, as long as you keep the contents of ~/.VirtualBox (including the .vdi files which identify the virtual HDDs). A new version of VirtualBox would find them. Only work would be to uninstall the GuestAdditions and install the later version.
No problem for read-only devices such as CDROM but can get messy for read/write devices such as USB memory sticks.

Good! It helps a lot to be clear about which is host and which guest

First of all sorry for late post i was out of town

So their is no problem if i remove my existing VIrtaulbox by issuing
would it remove my ~/.VirtualBox .
any suggestion

I'm 99.9% sure it wouldn't. You could make sure it doesn't by mv ~/.VirtualBox ~/.VirtualBox.aside and then moving it back to the original name afterwards.

In common with many software vendors VirtualBox's x.x.0 releases have new features which are bugfixed in releases incrementing the last part, the 0. For this reason you may find 3.0.12 more stable than 3.1.2 and so a better choice unless you want the latest features.

Are you having any issues with your current version? "If it ain't broke, don't fix it"!

I don't have any issues as of now but i just want to give a shot so I have downloaded VirtualBox-3.1-3.1.2_56127_fedora9-1.x86_64.rpm ,and i'm gonna install it and tell you if i got some installation error

I think I messed it up i installed the VirtualBox-3.1-3.1.2_56127_fedora9-1.i386.rpm and it shows a success message and i got a icon in my system tools but when i clicked it nothing happens , i add my user to vboxuser too .
This is what i got when i try to run Virtualbox in command prompt

I doesn't seem likely that yyou messed up -- the installation is pretty well automated. There are quite a few pages about _ZN8QPainter10drawPixmapERK7QPointFRK7QPixmap in the last year ...

I tried everything but nothing works any other solution or i have to go back to older version

Fixed the issues , just update the qt to 4.5 that'll do the job