Drive or processor

so, i got a dell laptop last year and it runs world of warcraft and dnd online fine, but it won't run things like the sims 2 or neverwinter nights etc. I thought that it was just my processor, but my drive seems to try to hard to run things. is anyone else having this problem, i have a dell inspiron 1525 with an intel pentium dual-core processor, i can't remember the exact number but i'm pretty sure its under 2ghz.

That laptop will take upto 4gb of RAM, also a SSD will make a big difference.