Need the system spec dude so we can help ya out more.
I run ubuntu on a very old laptop (2002-3 machine) and it runs fine on it.
Specs are a P4 2.0GHz, 1GB RAM, 30GB HDD IDE, some mega ass crappy intel graphics 64MB or less? i cant remember and i use one of those old school wireless cards that you slide down into the side of the laptop? all working perfectly.
The laptop doesnt have a DVD/CD drive, and wont boot from a USB drive, you ask how did you install the OS on it? i installed it from another computer, my old desktop, then put the HDD back into the laptop after it finished installing Ubuntu onto the laptop HDD via a USB connection and it booted up normally.