Some people have had a problem with sound after installing adobe flash player, i found loads of solutions to this on the adobe forum...ok it doesnt let me put in a web adress, email me on chrispepper1989 followed by an at symbol followed by gmail dot com (sorry it doesnt like emails either lol) and ill send you the link!!
look particularly at Gilhooley and BilalM explantations and solutions, apparently adobe sometimes removes a registory string called wavemapper and this is the problem look on the forum for more details.
OR you could just be like me and didnt realise the obvious, personally i had tried to set up a 5.1 surround sound system with normal speakers however i decided that i would rather have sound through rear and surround speakers....and then forgot about it....and gues what internet sounds only come through the FRONT speakers!!! i felt such a noob

, but do check it anyway, theres no point in trawling through the adobe forum if the solution is actually the front speakers!
as i cant put in a web address here is Gilhooleys full pst:
"YES! I fkin solved it!! Something breaks your registry settings under [HKLM\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Drivers32] so the Wave connection is missing, then it dosent matter if you have all you vp6 or mp3 codecs installed. Save the lines below as a textfile with a reg ending, like "missing.reg" and 2x click it to import it to your registry and your golden Or if you have most of them, "Wavemapper" is the one flash is looking for.
Windows Registry Editor Version 5.00
[HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Drivers32]
"midimapper"="midimap.dll"
"msacm.imaadpcm"="imaadp32.acm"
"msacm.msadpcm"="msadp32.acm"
"msacm.msg711"="msg711.acm"
"msacm.msgsm610"="msgsm32.acm"
"msacm.trspch"="tssoft32.acm"
"vidc.cvid"="iccvid.dll"
"VIDC.I420"="i420vfw.dll"
"vidc.iv31"="ir32_32.dll"
"vidc.iv32"="ir32_32.dll"
"vidc.iv41"="ir41_32.ax"
"VIDC.IYUV"="iyuv_32.dll"
"vidc.mrle"="msrle32.dll"
"vidc.msvc"="msvidc32.dll"
"VIDC.YVYU"="msyuv.dll"
"wavemapper"="msacm32.drv"
"msacm.msg723"="msg723.acm"
"vidc.M263"="msh263.drv"
"vidc.M261"="msh261.drv"
"msacm.msaudio1"="msaud32.acm"
"msacm.sl_anet"="sl_anet.acm"
"msacm.iac2"="C:\\WINDOWS\\system32\\iac25_32.ax"
"vidc.iv50"="ir50_32.dll"
"wave"="wdmaud.drv"
"midi"="wdmaud.drv"
"mixer"="wdmaud.drv"
"VIDC.WMV3"="wmv9vcm.dll"
"VIDC.VP40"="vp4vfw.dll"
"msacm.voxacm160"="vct3216.acm"
"MSVideo"="vfwwdm32.dll"
"MSVideo8"="VfWWDM32.dll"
"wave1"="wdmaud.drv"
"midi1"="wdmaud.drv"
"mixer1"="wdmaud.drv"
"aux"="wdmaud.drv"
"vidc.VP70"="vp7vfw.dll"
"vidc.X264"="x264vfw.dll"
"VIDC.FPS1"="frapsvid.dll"
"vidc.VP60"="vp6vfw.dll"
"vidc.VP61"="vp6vfw.dll"
"vidc.VP62"="vp6vfw.dll"
"vidc.DIVX"="DivX.dll"
"VIDC.UYVY"="msyuv.dll"
"VIDC.YUY2"="msyuv.dll"
"VIDC.YVU9"="tsbyuv.dll"
"VIDC.DRAW"="DVIDEO.DLL"
"VIDC.YV12"="yv12vfw.dll"
"wave2"="wdmaud.drv"
"midi2"="wdmaud.drv"
"mixer2"="wdmaud.drv"
"aux1"="wdmaud.drv"
"wave3"="wdmaud.drv"
"midi3"="wdmaud.drv"
"mixer3"="wdmaud.drv"
"aux2"="wdmaud.drv"
"VIDC.MSUD"="msulvc05.dll"
"wave4"="wdmaud.drv"
"midi4"="wdmaud.drv"
"mixer4"="wdmaud.drv"
"aux3"="wdmaud.drv"
"
but as some people may have already tried something similar please do email me the forum is worth goin through if you have this problem! hope this helps!