Hi Iftay,
Welcome to the HP forum!
Thank you for your post, I will do my best to help you resolve this issue.
I understand that your microphone is not working. Here is a link to a document I believe will help. Resolving Microphone and Line-in Problems (Windows 7). Here is a link to the software and driver page for your computer. Please select the correct version of Windows 7 to display the software and drivers.Drivers, Software & Firmware for HP 242 G1 Notebook PC. Please let me know if you require more help.