I had few issue with SP1a too. Then i suspect different chipset could be causing the issue.
My 845MP chipset that had SP1a works fine, although the OS is pirated but i paid the license. Just dun like the recovery CD for my laptop.
My 865PE chipset that had SP1a dun work fine. One moment, it disable my control panel's add/remove software. next moment, it disable my USB features... And the OS is the same CD i used.
Then again, you can always use a firewall whilst updating ur Sp1.
My 845MP chipset that had SP1a works fine, although the OS is pirated but i paid the license. Just dun like the recovery CD for my laptop.
My 865PE chipset that had SP1a dun work fine. One moment, it disable my control panel's add/remove software. next moment, it disable my USB features... And the OS is the same CD i used.
Then again, you can always use a firewall whilst updating ur Sp1.