Not enough memory! (likely video memory)

Please help! Together a PC

A couple of months everything was normal, due to not known reasons flew vinda! After reinstalling in not very demanding games began popping up error! I thought that Windows was crooked on this downloaded new and installed! Better but most games are not playable. For example, in Hurtword at startup appear artifacts after them, the game becomes transparent without sound, only responds to the closing, reinstalling game doesn't help And yesterday the video card all such things helped only reboot!