Toshiba Laptop makes beeping noise and then freezes

Here are my specs:

OS Version: Microsoft Windows 7 Home Premium , 64 bit
Processor: Intel(R) Core(TM) i3 CPU M 330 @ 2.13GHz, Intel64 Family 6 Model 37 Stepping 2
Processor Count: 4
RAM: 3894 Mb
Graphics Card: Intel(R) Graphics Media Accelerator HD, 1723 Mb
Hard Drives: C: Total - 464783 MB, Free - 434084 MB;
Motherboard: TOSHIBA, Portable PC, Base Board Version, Base Board Serial Number
Antivirus: avast! Antivirus, Disabled

I have a Toshiba Satellite A505-S6005.What's happening is my compuer and keyboard will stop responding and makes weird beeping noises after windows has been already running for a while. It's a slow beeping each are spaced out about a second or two apart and it beeps three to four times please help me.