Icons Keep Changing Appearance,finder Problems, 10.4.2


Hi there and I hope someone can help me please !
I have been a mac geek for about 8 years so fairly experienced.
Just got a dual 2.3 g5 with tiger pre-installed.
Updated to 10.4.1, no probs.
Updated to 10.4.2 and things have gone a bit weird !
When i press Finder to open my main window, all my icons have changed, everywhere !
They swap themselves around completely, so for instance, the documents icon has changed to the software update icon, library icon has changed to activity monitor, movies icon is now preview app icon and so on and so forth - In some windows all icons have changed into a fuzzy lined square, never ever seen this before !
On top of this nothing external is recognised on the desktop, be it ipod, cd's or dvd's ( I have to open quicktime, then open file and the disc appears in that finder window, but not the main one.)
Also, even when disc or ipod is removed, it will then appear in the finder window, with the eject arrow, but wont dissapear when eject is pressed.
I have found that if i log out and log back in then the disc inside the drive shows up on my desktop and the icons appear fine, only for a few moments, then they all change again.
I have set up new account with test name and it appears to be ok, but I need to know how easily to transfer all my accounts/settings and files etc from my old main named account, then to the new test account, which in theory I can do, then delete the old main named account and rename test with my username - is that right.............???
There must be an easier way to fix this small, but most annoying glitch and i hope someone can assist, as apple have been useless !!!
I have used disc utility from main disc, i have repaired disc, repaired disc permissions, it is totally doing my head in !!
Also looked at Finder preferences, they change by themselves, in Sidebar the top 6 are not ticked, they have a dash and do not make any difference when clicking on and off -
Sorry its a bit long and I really hope I can hear some useful tips please on what to do as this is driving me mad !
Many thanks in advance to anyone that wants to help me please !!