Help with video!

[becca.blood]

Sp I use a canon Rebel T2i, and everytime I try to edit a video using Windows Movie Maker it slows up my computer. Once I finally get finished with the video I made and upload it to youtube and everytime my video usually has pink and green lines that just randomly show up and ruin the whole thing. Whenever I do tha same thing with a different non DSLR camera nothing is ever wrong with it. Help me, I have tried everything! Thank you!