I have a compaq TFT450 lcd monitor which won't power up. The input
fuses on the 5v and 12v inputs are fine. After the each fuse there is
a 470 micro farad capacitor. I have a multi-meter but I am not too
sure on how to test the capacitors ?

To test the capacitors you will need an ESR meter. It is very well possible
that one or more electrolytic capacitors are bad. Coincedently I repaired a
Compaq TFT screen yesterday (randomly flashing lines); while tracking down
the cause of the problem I did notice that many of the SMD caps did have a
poor ESR. In this case the problem was caused by a bad electrolytic cap
near the power input.

--
Peter van Merkerk
peter.van.merkerk(at)dse.nl