That sounds like you just added a TV as an extra monitor, you didn't change anything about the actual CPU.
If it's a really small laptop with low RAM like 2Gb it might be that it's having trouble processing / connecting to a second screen, but unless you've actually added physical computer parts to convert the laptop to a more powerful pc you're going to have the same problems as with your original laptop just more now because you're taking extra RAM getting it to connect to external devices.