Strange USB HD Problem after 10.5.7 update

hey guys...i need some help...now the reason im posting this here is because i think this problem only started after my update to 10.5.7 ...it could be hardware related...but i cant be sure

heres the thing...i have 2 usb hard drives...both bus powered...earlier i could just eject one & connect the other...it all worked fine...but now if i had one connected...the other will not mount...it shows up in the disk utility...but wont mount

if i reboot...then it mounts & shows up...but now the other one wont mount till i reboot again...this is driving me nuts...ive never had a problem like this before...

any ideas on what may be going on...or how i can fix this problem...i look forward to any suggestions...thanks

Have you tried Repairing Permissions since the update?

Always find the best way to update is to download the combo updater from the Apple web site, disconnect all peripherals except keyboard and mouse and disable AV if any, run Repair Permissions, install, and after reboot , run Repair Permissions again.

yes...i have...i did not do it before installing...only after...but it did not fix the problem...im not sure what exactly is causing it...but i really wish it gets fixed soon...its a pain rebooting every time i need to switch a drive

ok...since nobody had anything to say...i have another thing to add...any idea if resetting the pram will help...what exactly gets reset when you do that?