Sound Problem on Brand New PC!

HI ALL...im facing problem with my sound card...im not sure whether it is sound card problem or drivers...im using windows seven on E7400 C2D with ntel D98 board...i was having PSU prob...n i went to the get it changed..bfr changing PSU sound was working well, loud n clear..its a brand new PC though...i took it home n tried some youtube videos n a very low scratchy sound came on full speaker volume...then checked ma speaker n tried others too..but nothing happend niether front nor back pannel is working..temme wat to do im confused...is it hardware or software prob plz help...

software

hw come..? explain plz...

theres a paroblem in Windows 7 on my desktop Pc theres a noisy sound and on my laptop it runs perfectly no noise issue ...4 month back microsoft released a patch file for this particular issue.

Windows 7 is not yet officially released. Use either Windows Vista or Windows XP for the time being.

Currently Windows 7 Beta and RC are not meant for public use.

Hello peoples i know it is off. the topic but.. can any one tell me what is the best repair shop in karachi for notebook/laptops in karachi my DELL Latitude C400 have a problem of no display,, have working very fine since a year ....i hv visits Laptool in Regal ,any other shop u peoples know???? my no. 0300= 220 38 40 or mail me..