after I have installed new windows 7 my sound card works but my headphone jack does not create sounds. although it makes a very low hum sound. when I also take the pin a bit out it gives me the sound. it looks like there is something wrong with the jack configuration

"when I also take the pin a bit out it gives me the sound." That would seem more like some type of hardware problem. Frequently plugging and unplugging the jack can wear down the spring connection inside the jack. The timing of it may just make it appear that the upgrade is the problem...

no the problem was not the jack . it was an error that the driver could not adjust itself with windows 7 . I finally downloaded a windows seven compatible driver from Real teck official website and its now working perfect.