How to fix aspire 5552 no sound windows 7 ultimate +

Acer Aspire 7720, Signal Up, Intel Pentium Dual CoreExcellent condition £170 ONO
Selling my acer aspire 7720 signal up, used but in very neat & clean and immaculate condition, Comes with charger and laptop bag technical specifications are restore and Upgraded to Windows 7 Ultimate edition (Activated) Microsoft security essential Microsoft Office 2010 professional installed Intel Pentium Dual Core GHz Processor 250 GB SATA Hard Disk. 3 GB DDR2 RAM Crystel eye web cam 17' WXGA + CrystalBrite LCD Intel Graphic media DVD Super multi DL Sub woofers with Acer eAudio and built in DOLBY Digital Live system. Wireless internet. Good battery timing about one and half hours Left mouse button have some scuff of use otherwise in mint condition very fast and reliable 170 ONO For any further information please email me or call/ text on 07414495967