It could be the blade or...
Try traming the tablesaw. The blade is running sideways most likely. If so, it makes your saw very dangerous. I can lead to very nasty injurys from binding and kickback.
Under the saw......if the saw is worth anything, there will be an asjustment nut to loosten the saw and arbour assembly. Build a shuttle that has a dial indicator that runs allong the side of the blade in the 3/4" slot on the table. Make sure the blade dials in at .001" or so along its length and tighten the blade/arbour assembly down. I'm sure there are tutorials about this on the web somewhere.
Just make sure it is unplugged first, a no brainer but still should be said.