TX led stay on while arduino is running

Im realy frustrated with this probelm.
At first when i powered on my arduino uno,the TX led stuck on and my pc wasnt able to communicate with the board.
I fixed this problem by pressing the reset button and plugging my arduino to the USB.
And then i ran some programmes succesfully but the problem now is that even when the arduino is working properly,thr TX led stays on.
Can anyone help me with this??? :confused:

So when you upload the File->Examples-> 01.Basics->Blink sketch the 'TX' light comes on and stays on while the 'L' light is blinking? Do you have a ISP device so you can upload fresh firmware to the 16u2? This is how you would do that:

Notes: Change "-cusbasp" to match your ISP device. Change "-pm16u2" if your board has the older m8u2.

Change Directory to the Arduino "hardware" directory.

On Windows it is something like: cd "C:\Program Files (x86)\arduino-1.6.13\hardware\"

On a Mac it is something like: cd "/Applications/Arduino.app/Contents/Java/hardware/"

// MEGA update 16u2 tools/avr/bin/avrdude -Ctools/avr/etc/avrdude.conf -pm16u2 -Pusb -cusbasp -Uflash:w:arduino/firmwares/atmegaxxu2/arduino-usbdfu/MEGA-dfu_and_usbserial_combined.hex -Ulfuse:w:0xFF:m -Uhfuse:w:0xD9:m -Uefuse:w:0xF4:m -Ulock:w:0x0F:m

// UNO update 16u2 tools/avr/bin/avrdude -Ctools/avr/etc/avrdude.conf -pm16u2 -Pusb -cusbasp -Uflash:w:arduino/firmwares/atmegaxxu2/arduino-usbdfu/UNO-dfu_and_usbserial_combined.hex -Ulfuse:w:0xFF:m -Uhfuse:w:0xD9:m -Uefuse:w:0xF4:m -Ulock:w:0x0F:m

As for anyone working with Arduino I recommend you invest $3 to $12 in an ISP device so you can refresh/update the bootloader if you ever feel like it. You can get a USBasp clone from the far east for well under $5 via eBay. Search for "USBasp", Buy It Now, and sort by "Price + Shipping: lowest first":

http://www.ebay.com/sch/i.html?_sop=15&_nkw=USBasp&LH_BIN=1

Most come with just a 10-pin ISP cable and the Arduino uses a 6-pin ISP connector so you will need an adapter. At or near the top of the list you should see adapters, two for $0.99. Add one of those to your cart. Then scroll down until you find the USBasp devices (little circuit board with USB plug at one end and 10-pin cable at the other). Currently the lowest price is $1.66+$0.11 shipping ($1.77 total). (For a couple dollars more you can get a fancy one with a plastic case but some clear packing tape or shrink tubing will protect the bare board well enough.) Add one of those to your cart. Check out and pay and you will have your devices in a few weeks.

If you want it faster you can look for an eBay vendor in your country. For example if I click on the eBay option for "Item Location: North America" the cheapest price for the USBasp jumps to $3.49 and another $3.53 for the 6-pin adapter. Still, $7.02 isn't bad and it should arrive in days instead of weeks. If you want it in two days and have Amazon Prime you can get one for $5-6 ($12 for one including the 6-pin adapter).