cant upload sketch to microchip

avrdude: verification error, first mismatch at byte 0x0002
0x61 != 0x62
avrdude: verification error; content mismatch
Getting this error when trying to upload a sketch into atmega 328 using arduino uno rev3. Using arduino for widows on windows 8.
I tried everything i could: reinstalling drivers, immediately loading program into board after holding reset. Green led is on and yellow led flashes on pressing reset. Its just been less than 10 days since i have brought this board. It was working fine till yesterday. But suddenly failed to upload from today morning. The last successfully uploaded program into microchip is still there in it and working fine. please help . . .

please help some one

Have you tried uploading sketches from another computer? Then you can isolate whether or not the problem is your Arduino itself, or the computer. Windows 8 has been known to give trouble to the Arduino.

Mr_E

thank you will try