Thank you for the DxDiag.txt. The cpu is the most important component in video editing. The i5-2520m cpu in your laptop has a passmark score of 2266 : https://www.cpubenchmark.net/cpu.php?cpu=Intel+Core+i5-2520M+%40+2.50GHz&id=809 . You can get good useability on HD 1280 x 720 resolution video files by either setting the preview quality to high or enabling shadow files in PowerDirector for editing high resolution video files. You must let the shadow files finish processing first before attempting to edit if you go that route.

If you like to venture into 4K resolution video editing then a new pc with a better cpu passmark rating may be desired. See this post for details: https://forum.cyberlink.com/forum/posts/list/82821.page and this recent one: https://forum.cyberlink.com/forum/posts/list/84323.page .

welcome to the forum.
if you're keeping the old betsy then try to free up some C:\ 100GB HDD or SSD space.
my dell xps is decade old still i use it; however, i have 16GB memory, little bit faster cpu at 4517 and 134GB SSD free space.

here is wd mybook 4tb external hdd at a reasonable price. free shipping of course.

happy happy joy joy

PepsiMan
'garbage in garbage out' 'no bridge too far'

Yashica Electro 8 LD-6 Super 8mm
Asrock TaiChi X470, AMD R7 2700X, W7P 64, MSI GTX1060 6GB, Corsair 16GB/RAM
Dell XPS L702X i7-2860QM, W7P / W10P 64, Intel HD3000/nVidia GT 550M 1GB, Micron 16GB/RAM
Samsung Galaxy Note3/NX1