What size bolt do i use to mount my regza toshiba to a wall mount, 47 in.

its better to send it to repair shop

where can I get a replacment stand for a toshiba W42LT66

You will use the bolts that you take out to remove the base from the tv.

It is very likely that the correct mounting bolts to attach a wall mount to your TV are type M8 bolts 20 MM long. It is a rather standard size and you should be able to find them locally without a problem. This is the most probable size although you may find that it requires a different size. It should be either a M5 or M4 bolt of similar length. Give it a try, I think you will find it works perfectly!

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.

the stand just slots into the bottom of the tv and you just tighten it with four bolts provided.

if your GF wants you to separate the three in one coffe what well you do?

The bolts that hold the wall mount bracket to the TV vary in size depending on the manufacturer of the tv you have.

The best thing to do is to purchase a wall mount bracket specifically made for your TV.

It may be possible that your owners manual will list the size of the bolts you will need.

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

forget the four holes on the bottom of the stand. Remove the five allen bolts on the back bottom of the tv-not the stand. Yank on stand and metal plate slides out with stand.