Performance suddenly drops from 80fps to 25?

[ireviewmod]

I have i5 3210m @ 3.0/3.1ghz, intel hd 4000, 4gb ram, I have fully updated drivers, and in minecraft on low settings with medium render distance i get like 25 fps?! And the wierd thing is, once i got the pc, i had 80 on max? I don't know what happened, it is definately not a virus, i never had one, i have an anti virus and a fresh computer with still over 500gb of space? Alot of people say its because my dedicated video ram is only 32mb? anyway to make it 64? or something? On minecraft I had the shadow mod, and I got 40 fps, now 9? Please help thanks, before, the minute i turned on my laptop and got it running, minecraft was PERFECT, ma graphics 80 fps, now I play on low and i get 20-25, its insane, and this happened in every game, I have fully updated drivers, any help please?