CAN I GET SCREW HOLE SIZE OF BACK OF TV FOR WALL MOUNT

If you mean from the wall mount to the tv, that is usually embossed on the back by a screw hole usually five a Max 10 or something similar. If you mean to the wall that depends on the type of wall material. Use high quality anchors. Your local hardware store should be able to help you choose what is appropriate for your wall material.

Not sure what you are asking. Are you looking for the screw for the attaching the mount to the TV or the mount to the wall.
If you are looking for the screw size for the back of the TV, it could be metric size M6 or M8. Just be careful of the length. Too long and you will ruin the TV. Maybe google the TV model and it might show in the owner manual the exact screw to use.

sounds like the wrong bracket for that TV.

it's simple get the size of the hole of your wall mount that's it

M8 - according to a document I found online for a Toshiba mounting bracket kit for their LCD TVs the bolt size is M8. It should be easily available in a large hardware store or place that sells large flat screens.
Make sure you hand tighten it into the mounting hole before attaching any brackets, to judge the proper depth for tightening. Over-tightening with a long bolt could damage the TV.

I'm told you have to force the M4 screws to fit. This is a computer monitor with a TV Tuner not a TV with a computer input. It was not designed for wall mounting.

any hardware store will have them bring your tv manual with you it will tell you the spec on the screw to connect to the 4 pre existing nuts on the back of the tv as far as from the mount to wall it will be a standard lag bolt small enough to fit threw the hole and long enough to go threw the drywall and about an inch and a half of the studd 2" to 2 1/2" inch lag bolt will work

The size is #8-40 X 3/4". This is a specialty screw, so you're screwed

The screw holes are metric. The set is supplied with M5x25 screws to attach the pedestal, so the wall mount screws will be in that same range.