Seriously ur pentium is a dinosaur. ..cant do hd video

just slot in any discrete gfx. even one from a few generations ago like geforce 240 or radeon 4850, available for like 30 or so bucks or less on the 2nd hand market.
your rig can watch HD movies with no issues then. your onboard gfx eating into your system ram as well probably. no need to change whole rig.
TS request reminds me of a chinese idiom:
得寸进尺 or "Give an inch and they’ll take a yard"
With $30, it is impossible to ask for it to work like $300..