first of all.......hi every one!

now back to the prob,


i wouldnt put this into any anti virus or a malware problem.

this is likely a deleted registry key or something like that. whenever he starts "yahoo messenger" the system restarts.

with yahoo starting and some yahoo key conflicting with the normal running dll or something like that, so the system restarts.....

the system will also restart, if there is something conflicting with the display drivers.
"amd" computers usually come equiped with "ati" graphics card and that sometimes conflicts a lot....if not updated.

am thinking.......
1) uninstall yahoo totally. by totally i mean, remove messenger, toolbar, updater, basically everything that says yahoo on it
2) run a registry cleaner (my fav is tuneup)
3) install yahoo messenger again
4) post here again

that should do it.