iPad 2 doesn't sync apps purchased or free downloaded from PC?

I can purchase (free apps or paid apps) from the store on my pc, but when i go to transfer them wirelessly or through connection through usb, my ipad is unable to sync these purchases. it doesn't do anything.

the only way i could get new purchases up until today was backing up my files, factory reset, then reinstalling my data.

today i tried that, but the recently purchased app for my son wasn't present. i tried syncing again, but nothing new. no newly purchased app has synced over.

i made sure all my apps were up to date on my pc.

i have tried closing my itunes and restarting it, and unhooking my ipad from the pc and reconnecting it. i have the latestd software installed.

i'm at my wits end.

this is also the same problem going on with my super ancient itunes2.

much help would be appreciated. any help would be appreciated.