My video keeps freezing but the audio keeps playing so my lips get out of sync

Please help!!!!!!!!!! I'm trying to make music videos but the audio is too fast for the video!!!!!!!!!!

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Computer Specs: Manufactuer: Gateway
Model: DX4860
Processor: Intel(R) Core(TM) i3-2120 CPU @ 3.30 GHz
Ram: 8.00 GB
System Type: 64 bit
Windows 7 Ultimate