Arduino problems. PLease help

I think my arduino is broken. I have tried plugging into my win7 laptop and it doesn't appear in Devices and Manager. It also doesn't respond on my Win XP. computer either. It doesn't even make the sound that it usually makes when a USB device is inserted. Note - i have tried many different cables so I don't think that is the issue. I think it may have been because I accidentally left it on over night with a 9V battery to the barrel jack with no other electronics hooked up. please help Is there any solution to this problem or am I completely screwed?

Also the L LED is stable. It blinks twice when plugged in and then is stable.

My arduino board does not seem to be working. I run Windows XP and it doesn't show up in the Device manager under Other Devices or COM Ports. My computer does not make the regular sound it does when a USB device is plugged in. I've tested the wire already. Additionally whenever I try to upload a program it gives me the errror - avrdude stk500_getsync() not in sync resp=0x00. I tried the arduino on a different windows 7 computer, i didn't get the same error as this but the computer does not recognize the board and neither does it make the usual sound. Just as before it is not seen in Device Manager. I've tried many different methods to try and fix this and my drivers are upto date I think. Now one small mistake i might have made is accidentally press the button 'Burn the Bootloader. Would this cause such problems and if so how would I fix it. Thank you in advance to anyone who has an answer. Please Help

Forgot to add - The arduino does actually power up with the L LED on Pin 13 being stable but the problems with the software continue.

Be sure to select the right board in the Arduino IDE. Look at Tools --> Board. Select the board you have connected then try again.

Elektrix

Tried that. I've selected the right board but it still doesn't work.

Until you can get the PC to recognize the USB connection when you plug in the board all other IDE commands involving communication with the arduino board are invalid. If it's not a bad USB driver installation then the board's USB serial communications function may be toast. I would suggest deleting any existing arduino USB driver and try reloading it.

Lefty

so if I'm not mistaken -- all i need to do is delete and then download IDE again.Correct me if I'm wrong. I apologize i am very new toelectronics all together

Kind sir, could you please walk me through how i would install theafore-mentioned drivers. Every tutorial online requires my arduino to be recognized in the Device Manager under the COM ports but this is precisely the problem I am facing.

usman204: My arduino board does not seem to be working.

Which Arduino? Where did you buy it?

Please don't use all caps in your subject lines. Everyone's problem is important.

Please do not cross-post. Threads merged.

I installed the arduino drivers and software. I uploaded blink. then I unlugged my arduio. Plugged it in again. My windows 8 laptop is not recognising it. My serial port in the arduino software is greyed out. I have decided too uninstall everything. Please give some exact step by step instructions as to how to re install it.

I'm using the Arduino Uno R3. I apologize for the All Caps

I fixed it. It was a problem with the port on the arduino that connectsto the computer. got it replaced, works like magic again